Choosing the right GPU to avoid CPU bottlenecking


Jan 25, 2007
Hi all
Given below is my system's current configuration:
Processor: AMD Athlon 64 3000+ (Venice Core)
Motherboard: ASUS A8N-E
Graphics Card: Gigabyte ATI RADEON X300 SE (GV-RX30S128D)
RAM: Simmtronics 512 MB PC3200 DDR400
PSU: Colorsit (450 W with double fan)
HDD: 1 Hitachi SATA 80 GB
Note: I plan to add 512 MB more so that I can enable the Dual Channel architecture.

I read some place even if I install the best GPU available in the market, there is a huge possibility that I might not get the desired performance because of CPU bottlenecking.
I logged on to Wikipedia and checked out all the Nvidia and ATI chip based CPU. I am not too sure what all I need to keep in mind to choose the right one. My current GPU is really SAD.
Also I saw that a few GPU's have a bandwidth of 42.2 GB/s, but PCI-Express architecture has max bandwidth of 8 GB/s. So what's the point in installing a GPU with such high bandwidth.
I would really appreciate if someone could explain me the theory behind choosing the right GPU, I would really appreciate that.


May 16, 2006
I have to head to the office, so I'll give my 2 cents short and sweet.
Someone I am sure will give you all inside info shortly.

Yes, with that CPU, and a top end GPU, you may not get the full performance the GPU can offer, but the performance would still be night and day over the GPU you have now.

The bandwidth of the GPU is not totally dependant on the bandwidth of the buss. There is no software or games that can begin to even use the total bandwidth of the PCIe buss. All of that GPU bandwidth is required to get the image on your screen fast, not through the PCIe buss.

If you buy a super duper GPU, the 512 meg of memory is going to be your biggest "bottleneck". Add another 512, then it would become a toss-up between adding another 1 gig of memory, or upgrading the processor.

You can always overclock your processor, a little goes a long ways here.
Depends also on the game. Most games are much more depandant on the GPU, than the CPU.

You will see a much bigger performance gain in your case by upgrading the GPU and memory, not the processor.

There will always be a "bottleneck" of some kind in your system. The bottleneck is simply the slowest part of your system. But it's all relevant.
Even if you have a 8800gts GPU and a Coreduo 6800, 2 gig of memory and Raptor Drives in RAID, you will still have a bottleneck.

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