Do yourself a favor: Lock everything down on 24bit/44.1khz When you do a final mixdown for a cd, you'll want to render at 16bit/44.1khz Unless you have a multi-bajillion$$ studio, you really dont need anything else. Going to higher rates only loads your computer down and gives you less horsepower, less plugins and bigger files before your system blue-screens. (the power users will come down in 3, 2, 1... but just go 24/44.1 and everything will be fine.)