Fast Writes

What exacly is "fast writes"? Is performance better with it on or off?

Thanks

Fast Writes is a feature implemented for Nvidia GeForce cards whereby data is written to the GPU from the processor directly. Enabling fast writes nearly alweays leads to worse performance. I would turn it off in the smartgarts tab for a 9500 pro. You need to reboot to make it so.

It was supposed to improve performance in certain situations. I read somewhere that on ATI cards it did not make difference. I've tried it on and off and indeed it does not make a difference.