Ok, up to now, I have not yet really made ALL steps, that were recommended by S.T.E.P.
What I did so far:
- Used "cccleaner" before new installation
- Installed Vanilla Skyrim with all DLCs (including the HD DLC) -> Steam NOT installed on the HDD with my OS
- Set up graphic card according to the AMD-Guide
- Cleaned the original plugins with TES5Edit (i.e. NOT Skyrim itself... but Update, Dawnguard, Hearthfires and Dragonborn, as recommended)
- Installed SKSE with plugins "Cell Stabilizer" and "OneTweak" (for using SBW... I heard, that it runs better with Radeon cards)
- Configed SKSE.ini with "ClearInvalidRegistrations=1" and "iTintTextureResolution=2048"
- Installed "ENBoost"
- PLUS installed the memory patch via "ssme" (https://www.nexusmods.com/skyrim/mods/50305/?) Or does this not work together with ENBoost? Apparently, it does...
- Using Mod Organizer with BOSS and Wrye Bash
- Downloaded and installed mods from the nexus (and cleaned some 2 or 3 of them with TES5Edit... mostly identical to master-records)
- Checked for incompatibility and installed patches, if there were any
- EDIT: using loose files, i.e. extracting all BSAs, except original ones
So far, I am experimenting with a merged patch from TES5Edit without leveledlists and a bashed patch for leveledlists. I made some minor ini-tweaks, but running with default "ugridstoload" (don't want to take ANY risk, if not neccessary)
According to Skyrim Performance Monitor, I'm not even using 2 GB of RAM or VRAM. I chose all the mods I want.... and I will NEVER again uninstall a mod, that was in a savegame before. Learned that already ;) As a matter of fact, I don't even want to install new mods into a running game. Heard, that this can also lead to problems.
To be honest... I haven't tried this setup properly, because I'm too afraid, that I will get CTD again :) I want to make sure, that I did all I could, before making another attempt.
Ok, infos about my "usual" problems: No freezes, no ils, "only" random ctd. There are no problems with interiors (except for strange stuttering without fps-loss when near candles). My problems are only referring to exteriors so far.
My system specs:
CPU: AMD Phenom II x4 @ 3.0 Ghz
GPU: AMD HD7950 PCS+ (3 GB VRAM)
RAM: 8 GB DDR-2
Sound: Creative X-Fi Platinum
SATA-HDD (no SSD) with enough space left ( > 20 GB)
If someone will tell me, how to hide text here like a spoiler or something, I would also like to post my modlist.
Edit: Sorry, I completely forgot to say "Thank you" for welcoming me :) So.... thank you. Any help is really appreciated. Folks at Nexus couldn't really help me :(
Edit 2: Just to make that clear... I'm not having ANY problems with other games whatsoever. And I have also modded Fallout 3 and Fallout: New Vegas, which can also be pretty unstable. But I was always able to fix problems. But Skyrim seems to be a little bitchy :)