When a cpu is limiting the graphic gard?

[AsusGraphics]

I have always been curious to know how one can match the graphic card so that the cpu isn't limiting it. I know there isn't way to know it 100% right but guidelines can be given.

What do you compare when you do the decision?

[v6ph1]

There is a good solution for testing:

Run a game in Benchmark mode with at least 2xAA.
Then do it again with 1 AA step less (if you use 2xAA then use no AA)

If the frames per second-rate is equal, you have a CPU limit.
If you have more frames in second test, you have a GPU limit.

an other test is the utilisation of cpu during the game.
with 100% you have a cpu limit.
if a dualcore has only 50% it also could be one.
Also for a quad core with 25%, 50% or 75%.

mfg
v6ph1

[AsusGraphics]

Can you know it by looking CPU and GPU specs? ^ is a good one to test if you already have the card but if you don't have it, what to do?

[v6ph1]

You need the whole spec of the cpu and the gpu - also hidden implementation details.
And you need the game, the solution of your screen and the detail level (AA, AF, shadows,...)

A comparision per specs (cores and frequency) will work only for components with the same architecture.
(You can compare a HD5xxx with an other one - but not with an GTX4xx)

A quad core cpu with 2.8 GHz or more won't limit any grafic card in todays games.
Also a HD5970 or a GTX480 SLI is limited by nearly all cpus.

Just search for a test with your favorite game in your solution and look at the fps-bars.

- v6ph1

[AsusGraphics]

A quad core cpu with 2.8 GHz or more won't limit any graphic card in todays games.
Also a HD5970 or a GTX480 SLI is limited by nearly all cpus.
- v6ph1

This is actually the point: can you estimate the above somehow without testing it?

If we presume that I play game with high or ultra high details, GPU is in a big role, that's for sure. But there is always the weak spot when the CPU cannot give enough information to graphic unit. Then it doesn't matter how fast your GPU is, because it cannot be utilized.

Since back computer was invented, there has been always opinions in the forums that is your CPU enough for the GPU. How are they estimated it? Wild queses?

[caballero]

A quad core cpu with 2.8 GHz or more won't limit any grafic card in todays games.
Also a HD5970 or a GTX480 SLI is limited by nearly all cpus.


So the HD5970 and GTX480 are an exception to what you've said?
And what about an overclocked core i7-980x extreme, would this limit these graphic cards?