Mac Pro 2.8 quad core, 16 gigs RAM, OS X 10.5.6 here, no problems whatsover. Had some issues with Lightroom and 64-bit processing for a bit but thats resolved now and anyways I think it was more a Lightroom issue than OS X. Same with the person's internet connection being dropped, that might not necessarily be an OS X problem. Could be router, modem, service provider, etc..