CPU Dependent?

Hi guys(and gals of course), I'm very close to a new system build and I have a question about CPU dependency in games. This is what I've heard, you push a system past 1280x1024 resolution in game (give or take) it bypasses the CPU and dumps all graphical work to the GPU (I could be all wet on that). I'm on a 22" LCD and all the games I play run extremely slowly, and I'd like to blame my 1.8GHz Opteron 165 but that would be contradictory to the statement above. My question is this, are games really CPU dependent (depending on the game engine of course I'm just talking in general here and of course since everything goes in and out of the CPU, everything's dependent on it to some degree)? I've got an HD3870 in my box of fun so I'd like to rule that out as a serious impact on my performance.

For a card like the 3870 only games like Crysis would be bottlenecked by the video card in 1280x1024. Almost all games would be bottlenecked by the CPU, especially the one you have Unless, of course, you're running some insane anti-aliasing settings..

If your board is capable, overclocking that chip is highly recommended, you should be able to get around another 1GHz out of it

Thanks for the reply Snod Bladder, I actually was thinking of purchasing a system with a 5400+ with everything. I really wish I could overclock but the RAM is just pathetic (won't even do 2MHz above the stock clock). I've heard that my ASUS A8N5X was decent (not good, but not bad) for overclocking, and once I have the money I might as well play with it since if I break it I can replace it. You've been a big help thanks again!

If the board gives you control over memory dividers, you could use those to keep the RAM clocks down

But, of course, it's up to you

CPU dependency for games (and benchmarks) is a bit of a tilting scale. I would refer you too this scale from a digit-life article, found here. The chart compares several video solutions and several cpu solutions, the goal of which is to show the difference between different levels of cpu and gpu, and their relative performance.

As you can see in that chart, if you take an 8800 GT (a bit faster than your 3870, but they are in the same class) and you see on the far right that the difference between an Athlon64 4000 and a Q6600 at 1024x768 in STALKER is a full 30 fps (102 vs 73), knock that up to 1280x1024 and its only a difference of about 9 fps (77 vs 68). If you look at Call of Juarez there is virtually no difference at either resolution. But the higher you go (in your case, 1680x1050) the more GPU dependent games become. Obviously some games will remain cpu intensive for things like physics or AI, but for higher resolutions, the difference between a $150 cpu and a $350 cpu becomes less prominent. But the difference between a $150 gpu and a $350 gpu becomes significantly more prominent.

For the highest of resolutions, such as 2560x1600 for example, you do need a powerful cpu that can in a sense "feed" the data to the gpu at a rate that it can still do its job efficiently. At such a high resolution most users will use multiple gpus, in crossfire or SLI modes, and when you do this the cpu becomes even more important because a lot of that gpu communication will rely on the cpu more heavily, as well as the software backbone in your games, drivers, and OS. This can also be seen quite well with certain benchmarks like 3dmark06 when you are using SLI or crossfire. You will reach a point that even overclocking your gpus wont increase your overall score very much, but overclocking your cpu will.

So really I dont think your 165 is really causing a bottleneck at this point, but overclocking it certainly wouldnt be a bad idea if you have the means. From what I recall all those chips typically managed to reach 2.4 without much trouble, hell I have an X2 3800 thats been running at 2.6ghz since the day I bought it a few years ago...and thats been going (and still is going) 24/7 with 100% cpu load.

I heard that the Opterons were only a mid-range product and they were mostly designed for servers. My Pentium 4 with a Radeon X1650 Pro (just upgraded the Mobo and CPU) are a pretty good combination, with brilliant gaming performance. My CPU is a P4 Northwood 2.8GHz (no hyper-threading HT).
In magazines I've read, the Radeon 3870 is a good performer, although the 8800GT is better. Custom PC reviewed a Dell XPS 630 System and said they could have got better graphics. But the 3870 should be able to play Half Life 2 at 1280X1024. Your Opteron CPU is too slow to run Half Life 2, as the CPU requirement is at least 2.8GHz/2.4GHz Dual/Quad-core. I would be thinking about a quad-core Intel at a speed of at least 2.8 GHz or and AMD Athlon64 X2 6000 at 3GHz. It's up to you what you want to do, but I certainly wouldn't recommend overclocking. It stresses the hardware, and it doesn't last as long. I recommend buying a new motherboard and CPU, at least your system could be future-proofed. Also, buy a CPU that fits your needs, that's why I bought the AOpen MX4SGI-N mobo with an Intel Pentium 4 Processor at 2.8GHz. By the way, your Opteron won't get anywhere with today's games, Mass Effect requires a 2Ghz dual core or at 2.4GHz single core, with at least Radeon 1300XT Graphics. So in Mass Effect, the graphics is a yes but the CPU is a no, if your Opteron is dual core, then 200MHz difference may work, but at lower resolution. I've seen quad core + mobo bundles for £222, so it's worth upgrading.
You've got to balance the graphics with the CPU anyway, having a graphics card that's probably faster than the system itself won't make any difference than a card that's the equivalent of the system. It's matching a card with a CPU, the 7600GT/Radeon X1650 works well on the P4. But the P4 wouldn't perform any quicker with a 3650 AGP. If you had a Geforce 1 in a P4, it would perform slower. Usually, If you get a graphics card that's faster than your current system can handle, you probably need to buy a new PC to go with it.
Hope this helps,
Soulman