For Roon itself - I like a dedicated PC/Box for it. Having a Roon Core, then Roon Remote takes all that extra processing work, threads, services from the playback PC. (I am waiting for RoonSpeakers to get back to my Roon Core, Roon Remote setup.)
The following is for Windows - Forgot to ask about which OS the OP was using…sorry.
Now if you like to tinker with your PC’s then the following are things people are doing for improvements. FYI I use 2012R2 Essentials, AO, JPLay, and Process Lasso on my dedicated Roon machines.
Here are some of what others have done for improvement in playback regardless of application being used. Now, how much each one makes in improvements is up to the end user -
People have cut back the number of processes running on their music machines. This is probably the most used “tweak” to get better playback. Audio Optimizer is a 2012R2 product that does that. Fidelizer is another product that works with Win8, 10, 2012R2.
Others have written scripts for Win 8 and there are recent threads about scripts for Win 10 reduction. (Script talk is over at Computer Audiphile).
NOTE: If you play with scripts, make sure you have a backup or image of your machine before changes.
Some people have used another ASIO driver (JPlay) and like the improvements.
Some have used Fidelizer and like the improvements.
Some have used Process Lasso and like the improvements.
Some have went to fan-less boxes in custom built machines, with custom interface cards and cables and liked the improvements.
Some have replaced SMPS (Wall Wart Power Supplies) with LPS (Linear Power Supplies) and like the improvements.
If using USB, some have reported improvement with the AQ Jitterbug.
If using USB, some have reported improvement with the Uptone Regen
If using USB, some have reported improvement with the Schiit Wyrd
Some believe in swapping cables, power conditioning, vibration control, and on and on for an improvement.
I am sure I am missing some other “tweaks” people are using.