computer isolation

Unlikely unless your laptop has tubes or uses a stylus to read a vinyl groove. Modern electronics is not micro-phonic. Frankly, if it was a problem then passive speakers would not work as the crossover would pick up vibration.

Just another urban legend.

As for the OP's question, there are probably more important things to try to optimize in you computer audio rig.

Exactly my point. The extent to which vibrations affect electronics has been greatly exaggerated due to people's experience with tubes and stylus (with a very high gain which is why you have a pre-preamp). These truths have created an urban legend in that people have extrapolated this to conclude that micro-phonics are a potential problem with all equipment - generally you don't have to worry about micro-phonics on a PC - although the physical noise of the cooling fan and the spinning of the hard drive can easily be an audible issue (especially if you sit next to the PC).