It does to some effect, although the numbers I saw are a couple of years old. I think it used to be a 20-30% performance hit for the databases that were encrypted as opposed to if they weren't encrypted at all. As far as actual hit on the processor or memory, I've not seen actual numbers. I need to do that research and update this article as this was written in the Windows 2000 days and there were some changes to EFS in Windows Server 2003.