I have also been having this problem recently.
- STEP 2.2.1, plus Texture Pack Combiner (with SRO) using 1k or 2k textures, and a few other non-graphical mods that my girlfriend wanted to install, like Convenient Horses and some **** where you get a pet fox or something
- ENB 0.155 and Phinix ENB
- Ultra in the launcher, but no AA/AF (PNENB handles the AA)
- 1920x1080
- Radeon 7950 3GB with 13.2 driver
- i5 760 @ 3.8 GHz
- 8GB RAM
- Skyrim installed on Crucial M4 SSD
- Hearthfire, Bethesda textures, no other DLC
- Unofficial patches
- NMM
- BOSS
Prior to crashing I often get purple/black textures, then a CTD not long afterwards. Frame rate is always fine, however, even prior to a CTD, and my video card fans/temps indicate that it's not struggling terribly. It nearly always crashes when I try and enter my Hearthfire house, and it also happened time after time trying to get into the Dawnstar sanctuary for the DB quest. Other than that it seems fairly random.
Skyrim Performance Monitor reports GPU usage between 80-100% normally, with VRAM at 2.8GB or below. It doesn't *seem* to be crashing due to hitting 3GB of VRAM, or at least that doesn't seem to be happening every time. But I can't be certain.
If I delete the Data folder from the TPC the crashes stop. I have not yet tried removing the Bethesda textures and retaining the TPC folder, but I'll give this a go.
What else should I try?