Dendi

Looks like I was able to fix the issue by doing the steps here and setting: minDistance = 3 maxSubdivision = 6 for KerbinOcean. I figured as much when the lag only appeared if the ground was in view. This wasn't an issue in the previous version at all for me, and I played without any issues with all default settings.

I'm having the exact same problem, with specs very similar to yours. When I go into the VAB it first shows weird texturing (image attached), which fixes itself after a few seconds. Unfortunately, the lag while I'm in the VAB makes it unplayable for now. I wish I could revert back to the previous version, but so far haven't been able to find out how