Ten worked for me on 4 cores just fine, and on 8 cores now as i get ready to get a full 80 group together it seems fine, I would look into a killer nic before ssd (and likely avoid it), using an actualy directx soundcard, and defiantly windows7.

I don't have problems in major cities, only one character has the actual sound device and the 9 don't have any sound. I find removing the minimap from the slaves helpful.

Fwiw, i do have problems with people spamming all the slaves with tells and the them spamming the main character or party chat and blizzard logging me out. It seems very very easy to hit that limit with 10 guys. This might be a increased by wim, prat and or icon chat. Kudos for the haters figuring that out.