I am thinking that you may want to play with that bible number 4096. Base on the combination of your os and platform, you might find a different bible number fits better. Can try something like 4096 *2, 4096 * 4, 4096 * 8 etc.
My guess is that, as long as you don't cause paging, bigger number would improve performance more. But if the number is bigger enough to cause paging, then it would hurt you instead.