For starters the pro version doesn't come with as much stuff as the ultimate install. It also runs noticeably lighter. The kicker? Your system will also score higher on the performance index rating when using Windows 7 pro over ultimate.

 

If it doesn't need to be connected to a network or the internet...

If you're going to run pro for a DAW with no network or internet  access requirements you're not necessarily going to need to down load all the security updates since there's nothing to secure so to speak.  It generally keeps the OS significantly faster and lighter without them.



Should be obvious but as ever there's always a few...

It's also advisable that you pass any files and apps that you want to use in it through an OS instance with full virus protection and security updates first to further reduce any potential risks.

Installing all the security updates for Windows 7 pro will in fact also noticeably degrade the overall operating performance and speed of your DAW even making it score lower on the system performance index ratings.

Turning off and removing devices that you don't use or need in your DAW will also mean less memory unnecessarily being used up and less process cycles being given over to things that aren't being used.