The Motherboard, Processor, and Memory - Overclocking Intel Processors
(Page 16 of 18 )
You will need a motherboard that allows you to change the bus settings in small increments.
On current systems, the bus’s native frequency will be 100MHz for a 400MHz FSB and 133MHz for a 533MHz FSB. (During normal operation, the bus is “quad pumped” to reach the higher frequencies.) Some motherboards let you increase the bus speed, which forces the processor to work at a higher frequency.
If you have an overclocking-friendly motherboard, you do the dirty work in the BIOS setup. Some manufacturers, like SOYO, ABIT, and ASUS, have a special page in the BIOS setup menu just for overclocking and performance tweaking your system.
To give you an example of bus overclocking, a Pentium 4 2.4GHz machine runs on a 133MHz bus with a 533MHz FSB. To get to 2.4GHz, the 133MHz is set with a multiplier of 18x. The multiplier is locked. Raising the bus speed, while keeping the multiplier the same, forces the CPU to work faster.
| Bus Speed, MHz | Multiplier | CPU Speed, MHz |
|---|
| 133 | 18 | 2400 |
|---|
| 134 | 18 | 2412 |
|---|
| 135 | 18 | 2430 |
|---|
| 136 | 18 | 2448 |
|---|
| 137 | 18 | 2466 |
|---|
| 138 | 18 | 2484 |
|---|
| 139 | 18 | 2502 |
|---|
| 140 | 18 | 2520 |
When you overclock the FSB, you have to watch that you’re not pushing the PCI bus or the AGP bus too hard. Whether you can overclock the FSB separately from those other buses depends upon the capabilities of the motherboard.
It’s helpful to use a benchmarking program, such as Bapco’s SYSmark or FutureMark.com’s PCMark, to see the results of your work. Be sure to run the benchmark before you begin your overclocking experiment to get a baseline, and then benchmark each increment you overclock.
It’s also helpful to run a utility that monitors the heat of your processor. Intel provides one for free. It’s vitally important to understand that, by overclocking, you increase the heat that your processor generates and you can easily age or damage the processor if you push it too hard.
If your computer hangs, reboots spontaneously, or if you start getting jillions of errors while running Windows and applications, back down the bus speed until the system is stable.
 This chapter is from Build Your Own High Performance Gamers' Mod PC, by Chen and Durham (McGraw-Hill/Osborne, 2004, ISBN: 0072229012). Check it out at your favorite bookstore today. Buy this book now. |
Next: Overclocking AMD Processors >>
More Computer Systems Articles
More By McGraw-Hill/Osborne
