It changes how much work the cpu does. The higher the interval, the more work is done on the gpu. It can cause lag though, so don't put it too high. Anyways, so man... how is your ppd so much higher than mine? It only works on the new 1.22 core. It definitely does something if you have that lol Normally the card takes a whole core in 1.22, but raising the interval can drop that about 60% now.