Well, you certainly would seem to have enough horsepower. I have a 4 year old lap top, a 256 GB SSD, 32,600 notes, a 17GB data base, and no response time issues, so it can be done. A few suggestions:
Hold the Ctrl key and press help in the EN menu. Then press optimize data base.
If you have Context turned on, turn it off, Tools - Options - Note - show Context.is at the bottom
Some say Instant sync causes issues (it doesn't seem to for me), so if you like turn it off, Tools - Options - Sync. If you leave instant sync on, set the synhcronize automatically window to every 30 minutes. But do remember to force a sync if you make a change on a mobile device and you return to your PC.
Advise if any of the above helps or not.