Memory Controller & Memory Bandwidth affecting FPS ..

[IceRedwing]

While more is better (enough with the less is better trend) how exactly does more bandwidth equate to better performance on video cards.

When I overclock, I see little increase in performance when I substantially overclock the memory in comparison to the core. I am curious because I noticed that in reviews they really rave about the bandwidth... and I just don't see any large gains with larger bandwidth.

Obviously I notice the difference in performance when you run a video card with a 64-bit / 128 bit / 256 bit memory controller. But based on the reviews on the 8800GT/GTS/GTX , the memory controller / bandwidth doesn't play much of a difference in the performance

 

[nullpointerus]

The faster the core goes, the more bandwidth it requires; otherwise, the core will sit idle.

The point of increasing memory bandwidth is to allow for higher core clocks. Once memory bandwidth is increased to the point that the core is no longer forced to sit idle waiting for the next piece of data, additional increases to memory bandwidth will have little or no effect on the framerate.

WRT your second question, I suppose that the GPU designers tend to overestimate the amount of memory bandwidth required and/or the memory controller tend to improve in ways we do not see (i.e. prefetch, latency, etc.) when we merely look at bandwidth numbers.