1) if you haven't already, try some isolation/support tweaks-I'm into low cost tweaks and partial to vibrapods combined with a maple cutting board
2) upgrade the power cord if it is possible
3) dampen the chassis-cheap again; go to Home Depot and buy the heavy duty black linoleum industrial floor tiles (not peel and stick) and attach internally with heavy duty double sided carpet tape, ensuring, of course, that you are not blocking ventilation holes
4) use power conditioning; if you don't want to blow your brains out money wise, spend $40 for a Quantum Electroclear
Doing all of this will give you a pretty significant performance boost in my experience.
2) upgrade the power cord if it is possible
3) dampen the chassis-cheap again; go to Home Depot and buy the heavy duty black linoleum industrial floor tiles (not peel and stick) and attach internally with heavy duty double sided carpet tape, ensuring, of course, that you are not blocking ventilation holes
4) use power conditioning; if you don't want to blow your brains out money wise, spend $40 for a Quantum Electroclear
Doing all of this will give you a pretty significant performance boost in my experience.