playing Ultra. no ini tweaks except ugrids at 9 and Exteriorbuffer =100. olny mods installed is the Texture Pack Combiner, and Project ENB. i've been making a loop from Riverwood to Whiterun for a horse, then to past Windhelm, then through the hot steam cracked tundra area, thro the foggy forest, back to Whiterun. i seem to be able to go about 30-45 minutes before freezing (rarely CTD). Skyrim Performance Monitor shows everything good. specs are...

GTX 670 4GB (not 2gig)
i7 z77 3770k oc'd to 42 (was getting the same frezes before ocing tho)
16gb corsair vengeance 1600
850tx v2

forever i thought it was a corrupt download of one of the many mods in TPC. even thought i'd narrowed it down to 1. but not sure now. anyone using ugrids=9 getting freezes after long excursions across exteriors? thanks!

Pretty sure upping the ugrid is the cause of instability.

The default is 5, and they say upping it to 7 is pushing the engine.

Yeah, no matter how good is computer specs, UGRIDS problem is something from Oblivion times. It's simply engine borders, which doesn't allow us
to see too far. I tried all possible tweaks and have crashes (at best setting i got crash every 2 hours).

Ah 45 minutes without crashing. I'd be happy with that. Although I really should be grateful for that jolt telling me to get back to work!

And to be OT, I tried ugrids 7 for a long time and got far less ctds than I do now at ugrids 5 but with more (and more complex) mods. Some people report running at 7 without problems as well.