Honestly I think its totally insane that anyone would run amazing charts on desktop class hardware. First, even if it can run out it why put your whole business in the hands of desktop class hardware. Desktop Class hardware fails, daily. Server grade hardware is built for reliability and fault tolerance. When configured properly, hard drives are in RAID (RAID1 or RAID5) or combinations of the two. Even if you back up AC every night your at risk. If you don't have AC, you can still treat patients but can you give them the same level of service. Do you have access to their charts, allergies, previous RX'es, etc... Without AC for 1 day would be a disaster. Every place I have ever installed and configured AC, the main computer has been some form of a HP Proliant Server (ML150, ML350, DL360, DL160, etc) Hard Drives were configured in RAID1, separate hard drive for backups, and AC online backup service.
Okay, some might say I'm paranoid, but when it comes to being with AC for one day everyone of my customers would call it a disaster.