Ultimate Overclocking & Stability Testing

.
.
.
.
INDEX


Part 1.: Ultimate Overclocking Guide - Click here

Part 2.: Ultimate Stability Testing - Click here

Part 3.: Test Your PSU's Rails With A Multimeter - Click here

~Disclaimer!

Everyday the number of persons, who are interested in overclocking rises. Also rises the number of overclocking computers number, and the number of ‘burned out’ systems. A lot of people are trying to overclock their precious system on their own, without knowing what the hell they’re doing. Hopefully todays systems are made with a lot of safety functions and this doesn’t really allow the person to ‘burn out’ their system, just like locking up, or rebooting due to high temperature, and then resetting itself the bios, and notifying the owner that the system has just recovered from an unstable overclock, and the bios settings are set to the default one. Also there are a lot of people who are ‘lazy’ and they don’t use Google or read the stickys at forums.

So, I decided that I’ll make a thread, where I’ll gather all the information (at least I’ll try – because it’s nearly impossible to gather all) what’s possible about overclocking, and to put them in one place in a clear and easy way, so that everybody can understand it.

In this guide, I just want to explain as clear as possible, what’s overclocking, how to overclock, how to troubleshoot an overclocked system, and everything what’s related to overclock. This will NOT be my own guide, I will be using lots of other sources (I will mention at the end of guide, those other sources, giving direct-link to them), but the idea is to have all the information at a single & same place, and people can read this, and understand how to overclock their system without problems.

So generally speaking, this thread contains all the information (I just hope) what’s required to help you understand how to overclock. I just gathered all the information from around 6-8 guides - see the end of the guide, to see all the sources.

WARNING: Overclocking can f*ck up your stuff. Overclocking wares down the hardware and the life-expectancy of the entire computer will be lowered if you overclock. If you attempt to overclock, this forum, its inhabitants, and ‘people who are appearing at the end of guide as sources’ are not responsible for anything broken or damaged when using this guide.
This thread is merely for those who accept the possible outcomes of this overclocking guide/FAQ, and overclocking in general.

Why would you want to overclock?

Well, the most obvious reason is that you can get more out of a processor than what you payed for. You can buy a relatively cheap processor and overclock it to run at the speed of a much more expensive processor. If you're willing to put in the time and effort, overclocking can save you a bunch of money in the future or, if you need to be at the bleeding edge like me, can give you a faster processor than you could possibly buy from a store.

What is Overclocking?

Overclocking is the process of making various components of your computer run at faster speeds than they do when you first buy them. For instance, if you buy a Pentium 4 3.2GHz processor, and you want it to run faster, you could overclock the processor to make it run at 3.6GHz.

The Dangers of Overclocking

First of all, let me say that if you are careful and know what you are doing, it will be very hard for you to do any permanent damage to your computer by overclocking. Your computer will either crash or just refuse to boot if you are pushing the system too far. It's very hard to fry your system by just pushing it to it's limits.

There are dangers, however. The first and most common danger is heat. When you make a component of your computer do more work than it used to, it's going to generate more heat. If you don't have sufficient cooling, your system can and will overheat. By itself, overheating cannot kill your computer, though. The only way that you will kill your computer by overheating is if you repeatedly try to run the system at temperatures higher than recommended. As I said, you should try to stay under 60 C.

Don't get overly worried about overheating issues, though. You will see signs before your system gets fried. Random crashes are the most common sign. Overheating is also easily prevented with the use of thermal sensors which can tell you how hot your system is running. If you see a temperature that you think is too high, either run the system at a lower speed or get some better cooling. I will go over cooling later in this guide.

The other "danger" of overclocking is that it can reduce the lifespan of your components. When you run more voltage through a component, it's lifespan decreases. A small boost won't have much of an affect, but if you plan on using a large overclock, you will want to be aware of the decrease in lifespan. This is not usually an issue, however, since anybody that is overclocking likely will not be using the same components for more than 4-5 years, and it is unlikely that any of your components will fail before 4-5 years regardless of how much voltage you run through it. Most processors are designed to last for up to 10 years, so losing a few of those years is usually worth the increase in performance in the mind of an overclocker.

Basic Terms of Overclocking

Chipset - A chipset is defined as “a group of microchips designed to work as a unit in performing one or more related functions.” As a general rule, today’s chipsets consist of two parts, a Northbridge and a Southbridge. Both of these terms will be discussed later, but the two working in tandem creates a better and more efficient flow of data with fewer conflicts. Common chipsets used with the Athlon XP processor at the time include the VIA KT400 as well as the nVidia nForce2. The nForce2 has emerged as a great chipset is the choice of overclockers.

Clock Multiplier - The Clock Multiplier is an internal setting of the processor that is used to determine the processor speed. As an example, if you have a processor that is set at the factory with a clock multiplier of 10 have a FSB of 100MHz, then the resulting processor speed is 1000MHz or 1GHz. It's a very simple and easy term but used frequently.

Double Data Rate (DDR) - Double Data Rate, or DDR as it is commonly called, is becoming very popular with the computer industry lately. DDR allows for the support of data transfers on both edges of each clock cycle (the rising and falling edges), effectively doubling the memory chip's data throughput. And even better is that all of the motherboards and the Athlon processors themselves support this feature. So not only can we double the effectiveness of our memory, but we can also double the speed at which data flows between areas of the motherboard too.

Front Side Bus (FSB) - In simple terms, the Front Side Bus (FSB) is the data path between the processor and the main memory. When used from an overclocker’s standpoint it is generally referred to as a speed measured in Megahertz (MHz). The higher the number, the faster the data flows.

Northbridge - The Northbridge is the portion of the chipset that communicates with the computer processor and controls interaction with memory, the Peripheral Component Interconnect (PCI) bus, Level 2 cache, and all Accelerated Graphics Port (AGP) activities. The Northbridge communicates with the processor using the Front Side Bus (FSB).

VAGP - VAGP refers to the voltage setting of the AGP port on the motherboard. Not all motherboards allow for the adjustment of this setting, but for those that do allow for it, the benefits can be great.

VCore - This is the voltage setting for the processor. This is where you can force your speeds to the next level, or completely fry your precious CPU.

VDIMM - This is where you set the voltage levels of your memory. Though higher voltages can help you achieve better overall speeds, they can also cause some system instabilities.

The Basics

To understand how to overclock your system, you must first understand how your system works. The most common component to overclock is your processor.

When you buy a processor, or CPU, you will see it's operating speed. For instance, a Pentium 4 3.2GHz CPU runs at 3.2GHz, or 3200 MHz. This is a measurement of how many clock cycles the processor goes through in one second. A clock cycle is a period of time in which a processor can carry out a given amount of instructions. So, logically, the more clock cycles a processor can execute in one second, the faster it can process information and the faster your system will run. One MHz is one million clock cycles per second, so a 3.2GHz processor can go through 3,200,000,000, or 3 billion two hundred million clock cycles in every second. Pretty amazing, right?

The goal of overclocking is to raise the GHz rating of your processor so that it can go through more clock cycles every second. The formula for the speed of your processor if this:

FSB (in MHz) x Multiplier=Speed in MHz.

Now to explain what the FSB and Multiplier are:

The FSB (or, for AMD processors, the HTT*), or Front Side Bus, is the channel through which your entire system communicates with your CPU. So, obviously, the faster your FSB can run, the faster your entire system can run.

CPU manufacturers have found ways to increase the effective speed of the FSB of a CPU. They simply send more instructions in every clock cycle. So instead of sending one instruction every one clock cycle, CPU manufacturers have found ways to send two instructions per clock cycle (AMD CPUs) or even four instructions per clock cycle (Intel CPUs). So, when you look at a CPU and see it's FSB speed, you must realize that it is not really running at that speed. Intel CPUs are "quad pumped", meaning they send 4 instructions per clock cycle. This means that if you see an FSB of 800MHz, the underlying FSB speed is really only 200MHz, but it is sending 4 instructions per clock cycle so it achieves an effective speed of 800MHz. The same logic can be applied to AMD CPUs, but they are only "double pumped", meaning they only send 2 instructions per clock cycle. So an FSB of 400MHz on an AMD CPU is comprised of an underlying 200MHz FSB sending 2 instructions per clock cycle.

This is important because when you are overclocking, you will be dealing with the real FSB speed of the CPU, not the effective CPU speed.

The multiplier portion of the speed equation is nothing more than a number that, when multiplied by the FSB speed, will give you the total speed of the processor. For instance, if you have a CPU that has a 200MHz FSB (real FSB speed, before it is double or quad pumped) and has a multiplier of 10, then the equation becomes:

(FSB) 200MHz x (Multiplier) 10= 2000MHz CPU speed, or 2.0GHz.

On some CPUs, such as the Intel processors since 1998, the multiplier is locked and cannot be changed. On others, such as the AMD Athlon 64 processors, the multiplier is "top locked", which means that you can change the multiplier to a lower number but cannot raise it higher than it was originally. On other CPUs, the multiplier is completely unlocked, meaning you can change it to any number that you wish. This type of CPU is an overclockers dream, since you can overclock the CPU simply by raising the multiplier, but is very uncommon nowadays.

It is much easier to raise or lower the multiplier on a CPU than the FSB. This is because, unlike the FSB, the multiplier only effects the CPU speed. When you change the FSB, you are really changing the speed at which every single component of your computer communicates with your CPU. This, in effect, is overclocking all of the other components of your system. This can bring about all sorts of problems when other components that you don't intend to overclock are pushed too far and fail to work. Once you understand how overclocking works, though, you will know how to prevent these issues.

*On AMD Athlon 64 CPUs, the term FSB is really a misnomer. There is no FSB, per se. The FSB is integrated into the chip. This allows the FSB to communicate with the CPU much faster than Intel's standard FSB method. It also can cause some confusion, since the FSB on an Athlon 64 can sometimes be referred to as the HTT. If you see somebody talking about raising the HTT on an Athlon 64 CPU and is talking about speeds that you recognize as common FSB speeds, then just think of the HTT as the FSB. For the most part, they function in the same way and can be treated the same and thinking of the HTT as the FSB can eliminate some possible confusion.

How to Overclock

So now you understand how a processor gets it's speed rating. Great, but how do you raise that speed?

Well, the most common method of overclocking is through the BIOS. The BIOS can be reached by pressing a variety of keys while your system is booting up. The most common key to get into the BIOS is the Delete key, but others may be used such as F1, F2, any other F button, Enter, and some others. Before your system starts loading Windows (or whatever OS you have), it should have a screen that will tell you what button to use at the bottom.

Once you are in the BIOS, assuming that you have a BIOS that supports overclocking, you should have access to all of the settings needed to overclock your system. The settings that you will most likely be adjusting are:

Multiplier, FSB, RAM Timings, RAM Speed, and RAM Ratio.

On a very basic level, all you are trying to do is to get the highest FSB x Multiplier formula that you can achieve. The easiest way to do this is to just raise the multiplier, but that will not work on most processors since the multiplier is locked. The next method is to simply raise the FSB. This is pretty self explanatory, and all of the RAM issues that have to be dealt with when raising the FSB will be explained below. Once you've found the speed at which the CPU won't go any faster, you have one more option.

If you really want to push your system to the limit, you can try lowering the multiplier in order to raise the FSB even higher. In order to understand this, imagine that you have a 2.0GHz processor that has a 200MHz FSB and a 10x multiplier. So 200MHz x 10=2.0GHz. Obviously, that equation works, but there are other ways to get to 2.0GHz. You could raise the multiplier to 20 and lower the FSB to 100MHz, or you could raise the FSB to 250MHz and lower the multiplier to 8. Both of those combinations would give you the same 2.0GHz that you started out with. So both of those combinations should give you the same system performance, right?

Wrong. Since the FSB is the channel through which your system communicates with your processor, you want it to be as high as possible. So if you lowered the FSB to 100MHz and raised the multiplier to 20, you would still have a clock speed of 2.0GHz, but the rest of the system would be communicating with your processor much slower than before resulting in a loss in system performance.

Ideally, you would want to lower the multiplier in order to raise the FSB as high as possible. In principle, this sounds easy, but it gets complicated when you involve the rest of the system, since the rest of the system is dependent on the FSB as well, chiefly the RAM. Which leads me to the next section on RAM.

RAM and what it has to do with Overclocking

First and foremost, I consider this site to be the Holy Grail of RAM information. Learn to love it.

As I said before, the FSB is the pathway through which your system communicates with your CPU. So raising the FSB, in effect, overclocks the rest of your system as well.

The component that is most affected by raising the FSB is your RAM. When you buy RAM, it is rated at a certain speed. I'll use the table from my post to show these speeds:
Quote:

To understand what this table means, look here. Note how the RAM's rated speed is DDR PC-4000. Then refer to this table and see how PC-4000 is equivalent to DDR 500.

To understand this, you must first understand how RAM works. RAM, or Random Access Memory, serves as temporary storage of files that the CPU needs to access quickly. For instance, when you load a level in a game, your CPU will load the level into RAM so that it can access the information quickly whenever it needs to, instead of loading the information from the relatively slow hard drive.

The important thing to know is that RAM functions at a certain speed, which is much lower than the CPU speed. Most RAM today runs at speeds between 133MHz and 300MHz. This may confuse you, since those speeds are not listed on my chart.

This is because RAM manufacturers, much like the CPU manufacturers from before, have managed to get RAM to send information twice every RAM clock cycle.* This is the reason for the "DDR" in the RAM speed rating. It stands for Double Data Rate. So DDR 400 means that the RAM operates at an effective speed of 400MHz, with the "400" in DDR 400 standing for the clock speed. Since it is sending instructions twice per clock cycle, that means it's real operating frequency is 200MHz. This works much like AMD's "double pumping" of the FSB.

So go back to the RAM that I linked before. It is listed at a speed of DDR PC-4000. PC-4000 is equivalent to DDR 500, which means that PC-4000 RAM has an effective speed of 500MHz with an underlying 250MHz clock speed.

So what does this all have to do with overclocking?

Well, as I said before, when you raise the FSB, you effectively overclock everything else in your system. This applies to RAM too. RAM that is rated at PC-3200 (DDR 400) is rated to run at speeds up to 200MHz. For a non-overclocker, this is fine, since your FSB won't be over 200MHz anyway.

Problems can occur, though, when you want to raise your FSB to speeds over 200MHz. Since the RAM is only rated to run at speeds up to 200MHz, raising your FSB higher than 200MHz can cause your system to crash. How do you solve this? There are three solutions: using a FSB:RAM ratio, overclocking your RAM, or simply buying RAM rated at a higher speed.

Since you probably only understood the last of those three options, I'll explain them:

To learn more about RAM timings, go here.

FSB:RAM Ratio

If you want to raise your FSB to a higher speed than your RAM supports, you have the option of running your RAM at a lower speed than your FSB. This is done using an FSB:RAM ratio. Basically, the FSB:RAM ratio allows you to select numbers that set up a ratio between your FSB and RAM speeds. So, say you are using the PC-3200 (DDR 400) RAM that I mentioned before which runs at 200MHz. But you want to raise your FSB to 250MHz to overclock your CPU. Obviously, your RAM will not appreciate the raised FSB speed and will most likely cause your system to crash. To solve this, you can set up a 5:4 FSB:RAM ratio. Basically, this ratio will mean that for every 5MHz that your FSB runs at, your RAM will only run at 4MHz.

To make it easier, convert the 5:4 ratio to a 100:80 ratio. So for every 100MHz your FSB runs at, your RAM will only run at 80MHz. Basically, this means that your RAM will only run at 80% of your FSB speed. So with your 250MHz target FSB, running in a 5:4 FSB:RAM ratio, your RAM will be running at 200MHz, which is 80% of 250MHz. This is perfect, since your RAM is rated for 200MHz.

This solution, however, isn't ideal. Running the FSB and RAM with a ratio causes gaps in between the time that the FSB can communicate with the RAM. This causes slowdowns that wouldn't be there if the RAM and the FSB were running at the same speed. If you want the most speed out of your system, using an FSB:RAM ratio wouldn't be the best solution.

Overclocking your RAM

Overclocking your RAM is really very simple. The principle behind overclocking RAM is the same as overclocking your CPU: to get the RAM to run at a higher speed than it is supposed to run at. Luckily, the similarities between the two types of overclocking end there, or else RAM overclocking would be much more complicated than it is.

To overclock RAM, you just enter the BIOS and attempt to run the RAM at a higher speed than it is rated at. For instance, you could try to run PC-3200 (DDR 400) RAM at a speed of 210MHz, which would be 10MHz over the rated speed. This could work, but in some cases it will cause the system to crash. If this happens, don't panic. The problem can be solved pretty easily by raising the voltage to your RAM. The voltage to your RAM, also known as vdimm, can be adjusted in most BIOSes. Raise it using the smallest increments available and test each setting to see if it works. Once you find a setting that works, you can either keep it or try to push your RAM farther. If you give the RAM too much voltage, however, it could get fried. For info on what voltages are safe, refer back to the Holy Grail of RAM.

The only other thing that you have to worry about when overclocking RAM are the latency timings. These timings are the delays between certain RAM functions. If you want more info on this, you know where to look Basically, if you want to raise the speed of your RAM, you may have to raise the timings. It's not all that complicated, though, and shouldn't be too hard to understand.

That's really all there is to it. If only overclocking the CPU were that easy.

Buying RAM rated at a Higher Speed

This one's the simplest thing in this entire guide If you want to raise your FSB to, say, 250MHz, just buy RAM that is rated to run at 250MHz, which would be DDR 500. The only downside to this option is that faster RAM will cost you more than slower RAM. Since overclocking your RAM is relatively simple, you might want to consider buying slower RAM and overclocking it to fit your needs. It could save you over a hundred bucks, depending on what type of RAM you need.

That's basically all you need to know about RAM and overclocking. Now onto the rest of the guide.

Voltage and how it affects Overclocking

There will be a point when you are overclocking and you simply cannot increase the speed of your CPU anymore no matter what you do and how much cooling you have. This is most likely because your CPU is not getting enough voltage. This is very similar to the RAM voltage scenario that I addressed above. To solve this, you simply up the voltage to your CPU, also known as the vcore. Do this in the same fashion described in the RAM section. Once you have enough voltage for the CPU to be stable, you can either keep the CPU at that speed or attempt to overclock it even further. As with the RAM, be careful not to overload the CPU with voltage. Each processor has recommended voltages setup by the manufacturer. Look on the website to find these. Try not to go past the recommended voltages.

Keep in mind that upping the voltage to your CPU will cause much greater heat output. This is why it is essential to have good cooling when overclocking. Which leads me to my next topic...

Cooling

As I said before, when you up the voltage to your CPU, the heat output great increases. This makes proper cooling a necessity. Here is a good set of links related to cooling and a few other topics.

There are basically three "levels" of case cooling:

Air Cooling (Fans)

Water Cooling (look here)

Peltier/Phase Change Cooling (VERY expensive and high end cooling)

I really don't have much knowledge on the Peltier/Phase Change method of cooling, so I won't address it. All you need to know is that it could cost you upwards of $1000 dollars and can keep your CPU at sub-zero temperatures. It's intended for VERY high end overclockers, and I assume that nobody here will be using it.

The other two, however, are much more affordable and realistic.

Everybody knows about air cooling. If you're on a computer now (and I don't know how you'd be seeing this if you're not ), you probably hear a constant humming coming from it. If you look in the back, you will see a fan. This fan is basically all that air cooling is: the use of fans to suck cold air in and push hot air out. There are various ways to set up your fans, but you generally want to have an equal amount of air being sucked in and pushed out. For more info, refer to the link that I gave at the beginning of this section.

Water cooling is more expensive and exotic than air cooling. It is basically the use of pumps and radiators to cool your system more effectively than air cooling. For more info on it, check out the link that I gave next to water cooling before.

Those are the two most commonly used methods of case cooling. Good case cooling, however, is not the only component necessary for a cool computer. The other main component is the CPU Heatsink/Fan, or HSF. The purpose of the HSF is to channel heat away from the CPU and into the case so that it can be pushed out from the case fans. It is necessary to have an HSF on your CPU at all times. Your CPU will be fried in a matter of seconds if it is not.

There are tons of HSF's out there. For a ton of info on HSF's and everything that goes with them, check out this page again. It basically covers all you need to know about HSF's and air cooling.

Critical Overclocking Programs You’ll Need

CPU-Z: General System Monitor and report.
ClockGen – optional: Make sure your get the version for your Chipset. This program allows you to Overclock from within windows. Not always as reliable as physically changing BIOS settings, but gives you an easy way to play with your settings without dozens of reboots.
Memtest86: You'll need to run this from a Floppy or Bootable CD. This basic program is still considered the best for testing your RAM
SuperPi: Intensive mathematical program that stresses CPU/Memory pretty extensively. I like this program because it gives you a good indication of your overclock in under a minute’s time.
Prime95: Clearly one of the best stability testers – used by all of the overclockers. It’s kinda old software, but it’s damn good.
MBM5 or SpeedFan: Monitor your temperatures, voltages while you’re in Windows or any OS. It’s one of the ‘must’ softwares. Why? Because you can not always reboot to see what are your temperatures, these aren’t always accurate, but they’re clearly better then nothing

Critical Components for a Quality Overclock

POWER SUPPLY (AMD & Intel)
Power Supplies are missed so often when it comes to figure out why your system isnt overclockig the way it should. DONT SKIMP HERE! Get yourself a quality Power Supply and you'll never regret it. The Power Supply that comes with most cases is garbage. If budget is tight, Go with an ANTEC or ENERMAX case. These usually come with a pretty decent supply. For detailed Power Supply Information, see DavidHammock's Power Supply Guide, Pandaking's Guide, theblackmages' Guide.

RAM (AMD & Intel)
A64s LOVE TCCD based ram. see Tim's TCCD Memory Guide for the best options.
There are several more factors that go into a quality and Stable A64 Overclock, that there are with Older XP
and Intel based systems. A few of the factors we need to take into Consideration are

CPU Multiplier (AMD & Intel)
All A64s are at least Half Locked. This means that you can set the CPU Multiplier Lower than
stock, but not Higher. This is a Good thing. Very rarely with A64's would you ever need to raise the CPU Multiplier over the Factory setting. The exception to this are the FX chips, they are fully unlocked.

CPU Voltage (AMD & Intel)
Most A64s have a default voltage of 1.4v to 1.6V. A64s are extremely efficient and usually can only take about 1.7v before they just start producing excess heat. I've run my Mobile up to 1.9v but found it did NOT help my overclocks and simply caused the CPU to produce enormous amounts of heat. These are NOT XP-M chips! While I doubt that running voltages between 1.75 and 1.9 will cause any permanent damage, it certainly has not shown to be beneficial in any tests I’ve seen so far.

HTT Frequency (AMD only)
A64s don’t use a traditional Front system Bus. Instead they use a HyperTransport. I can only assume its abbreviated "HTT" to differentiate between Intel’s "HT" and Hyper-Threading Technology. They are VERY different.

The HyperTransport is what controls the base frequency for communications and CPU speed in our A64 System.
The CPU Speed is controlled by the HTT Multiplied by the CPU Multiplier, The HyperTransport or Memory controller is controlled by the HTT Multiplied by the HTT Multiplier, and Memory speed is controlled by the HTT Frequency, Multiplied by the CPU Multiplier and then DIVIDED by the Memory Divider. That’s a bit confusing for most folks. And it took me a while to grasp the concept as well.

HTT Multiplier (AMD only)
Most AMD Motherboards are designed to handle an 800-1000 MHz Hyper Transport bus. Factory Default on 754 CPUs is 800 MHz (A 4X Multiplier) and 1Ghz (5x) on 939 CPU's this is a Critical part of Overclocking an A64 to the Max. Pushing the HyperTransport past 1Ghz can cause all kinds of system instability that is commonly misconceived as "I maxed out my CPU" or "My Ram is holding me back"

Memory Divider (AMD & Intel)
This is one of the most Confusing aspects of A64 Overclocking. There is ALWAYS a memory divider.
Setting the Memory to 1:1 means that the HTT bus is multiplied by the CPU Multiplier and then Divided by the CPU Multiplier to set the Memory speed. This means that it is OK to run your Memory at its peak efficiency and still go higher with your HTT bus if your CPU can take it. Take note that I said its "OK" not advisable. There are still sufficient tests out there showing that running a 1:1 ratio will garner you the best overall performance. I plan on adding a few test results in the next week or so showing the difference in performance using a higher memory divider than CPU Multiplier.

Since A64's use an On chip memory controller, the Ratio must be calculated a bit differently than old. 5:6 is NOT always 5:6. See that chart at the end of this post for a prety darn close representation of what each divieder is doing. Thanks to Oskar from DFI for the chart.

Memory Voltage (AMD & Intel)
Most motherboards offer a degree of memory voltage options. The memory of choice lately has been Samsung TCCD Based modules with Brainpower PCB's. These Modules run at 2.6v stock voltage, and can usually do no better with voltage up to about 2.8-2.9 volts. There have been a few reports of better settings with voltages over 3v, but these seem to be pretty rare
situations.

Most other memory can benefit from having additional voltage run through it. The king of this is the elusive Winbond BH-5 based memory modules. If you’re lucky enough to have some of these, you may want to invest in an OCZ Memory Voltage Booster if your motherboard is compatible as these can run some very impressive timings with a lot of voltage....
Speaking of Timings...

Memory Timings (AMD & Intel)
There are 5 Numbers in our Timings that we need to worry about a lot. Personally, I would like to learn more about the other numbers, but as of this writing, I'm pretty much in the dark there.
What we do need to worry about are CAS Latency, RAS to CAS Delay, RAS Precharge, and Cycle Time(Tras), and CPC (command Per Clock).
Ideally, we want these timings to be 2-2-2-5 1T. Most TCCD based module does this at 200 MHz (DDR400) and can usually go up to 215-220 with a Bump in Voltage to 2.7, and then we need to loosen them to go higher. 2.5-3-3-7 is still considered reasonable memory timings for an A64 system, and some people even go out to 3-4-4-8, but I would personally advise against using timings that high with an A64 System. We ALWAYS want to use CPC (1T) this means the Command per Clock interface is enabled. 2T performs extremely poorly on A64 systems. But since our memory controller is on the CPU, the Double Sided memory problem that plagues XP Motherboards is not evident. Give AMD a WOOT for that one.....

Chipset Voltage (AMD & Intel)
Usually just a small bump in Chipset Voltage will stabilize a flakey HTT bus. 1.6 is Stock on most motherboards, but 1.7 to 1.8 is acceptable as long as you have decent cooling on your Northbridge chip. Many A64 Motherboards use Passive heatsinks on these chips so before you install your dandy new A64 system, take off your NB Cooler and replace the Factory thermal past with some AS-5. This is usually enough to keep the MB Cool enough to run the extra voltage. Placing Ram Sinks on your Southbridge and any other heat producing chip is never a bad idea either.

AGP/PCI Lock (AMD & Intel)
The AGP and PCI Bus' are tied together on all motherboards that I know of. They are also derived from the FSB (Or HTT in the case of AMD) frequency by a divider. NVidia NForce chipsets have whats called a PCI/AGP Lock. This keeps your PCI and AGP Bus at a constant speed no matter what your HTT bus is. This is CRITICAL. If your PCI bus is too fast, you WILL corrupt hard drive data. If your AGP Bus is too fast, you WILL have Video problems. Via Chipsts have been known to have Faulty PCI locks. This appears to be corrected in the KT800 Pro Chipset, but KT800 and below SHOW a PCI Lock in most bios's but it doesnt do much... This is a Primary reason why overclockers stay away from these boards.
On your Nforce or Via KT800Pro board you want this setting at 33Mhz if its listed as a PCI lock, or 66-67Mhz if its listed as a AGP Lock. Pushing this offers absolutely no benefit as the bandwidth provided by these frequencies is more than todays Hard Drives or AGP Video cards can use.

COOL N' QUIET (AMD only)
Disable this. This is a feature that will automatically UNDERCLOCK your system if it feels it doesnt need to run so fast... Who are "They" to tell us how fast out CPU should run?