No problem. But, pseudo-expert, lol.
A domain, in my opinion -- but this has been a fun discussion on here for years -- is better, but it does bring DNS into the equation. If you don't mind, since the IP addresses will be private, can you post your ipconfig /all on your server and at least one of your slow machines? Are you using just one NIC card? When you have been running for awhile, what is your memory distribution? In task manager, how much memory is your old EMR using and Medisoft?