The CPU factor/VGA Charts

I notice there isn't usually much talk about the effect of your CPU when considering video card performance.

Like on the THG "VGA charts" they use a high end cpu I think, so that it won't be the limiting factor (bottleneck) thereby isolating the gfx card. But how useful is it when you have an old cpu?

We need to know what's the minimum processor required to fully "drive" the card in question. That would vary from game to game tho. So the max of the min of those I play is what I need to know.

This tells me whether the relative performance gain will actually occur for me.

After all, an 8800 and 6800 would give the same performance on a 386 running Win3.1.