Most poeple interested in getting the best out of their PCs in terms of SQ have probably already stumbled upon "The Art of Building Computer Transports" document. Among other things it recommends turning off most of your operating system (even to the point of killing explorer.exe!) so that nothing disturbs the flow of music.
Well, it is not very practical to say the least but I've found an interesting alternative, so called Game Booster. It is meant to free as much system resources for a chosen application (foobar in my case) as possible, temporarily stopping all the unncessary processes, so essentially its more or less what was recommended for top music performance. Only difference being that you don't have to cripple your OS and its a one-click thing.
Honestly, I couldn't tell much difference but I may be not the sharpest ear out there, so I'm curious about your opinions and experiences with this. Enjoy testing and do share.