Many have found that too frequent time sync can cause dropouts as the time is a higher priority that FT8 when it comes to CPU resources.

I would think a time sync of NO LESS than 30 minutes would be great for all but the driftyist clock chips. Typically, 1-3 hours would probably work. Just keep an eye on the Band Activity window and watch the DT column. If it starts approaching 0.5s overall, then adjust your time to a bit more often, but don't overdo it. It will NEVER be 0.0s as everybody's clock is slightly different. And you have a 2.5s window for FT8 and 1.0s for FT4.

I echo the others in saying that Dimension4 has long outlived its usability as there are better ways to sync your clock. I use BktTimeSync (its FREE), but that's just my choice since it can also use a GPS dongle to do all the heavy lifting, which I do. If you choose this one, make sure to click the lower left option "Reduce in system tray" which continues to run in the background and not lower right option "Close" which will exit and shut down.

--
73's
George - WB5JJJ
Hams over IP #100105