Ok, so my PC stands on a floor made of wooden boards that have a lot of space underneath, solid and all but still works like a big speaker box in a way. I thought about just using additional rubber feet (my Thermaltake X71 Core has some already) to reduce vibrations, but I want to go one step further and put whole PC on some kind of anti-vibration mat. First thing that comes to my mind is those mats that are sold for washing machines, but I'm wondering if rubber that those are made from is not too stiff/hard, works for watching machines but might not for PCs. I did a bit of research and I've found some that are more foamy..but I'm not sure how this will work in this situation. Also there is whole set of materials (pre cut or in sheets) used to sound-proof computer cases. But I'm not too sure it will work in this case..
Any suggestions are appreciated.