I saw many threads posting about game freezes on very highsettings on high end cards, I also had it at very high settings. I resloved it by migrating windows to SSD. in the video I show the RAM and HDD usage when lag spikes occur and then i show how they disappear when windows is on SSD in same area.
Texture settings are set to very high, shadow cache is off rest all was set by Nvidia for my GPU.. I get average 60FPS on very high settings @1080p and no lag after doing this