It was a while ago I played DAO but whilst playing it this week the game kept crashing to desktop and was totally unplayable when I entered Denerim. I use MODS and yes also a texture mod.

Seems the "memory leaking" was the culprit. I do own the game on Origin not GOG, or Steam.
The crash in Denerim made the game not load anymore. I solved the problem with this patch and haven't had a crash or hiccup since.

http://www.ntcore.com/4gb_patch.php

I play on windows 10 with AMD cards in crossfire and switched on.

I browsed for solutions but nothing helped and I did not encounter this solution.

I think the real problem with dragon age origins is the frame buffer effects. By disable them I was able to play with no crash. But the game still reboot my pc once in a while so I had to limit the cpu core to 2.

DAO regularly crashed in Denerim, Unchecked Frame Effect, and switched the affinity to 1 logical processor/core on running the launcher, and started a new game ... still had a crash in Denerim when I either tried to save the game or exit Denerim.
So I skipped Denerim for a while. Loaded the game prior to enterring Denerim. Did the Circle, the Dalish forest camp, and part of the Dalish mines. Did one task, tried to save in Denerim, and crashed.
New Problem. The ToolSet can read a file, let me edit, but then crashes when trying to save the change. It worked just fine until yesterday. Tried to delete old saves, no effect.

x-64 based PC, Windows 10, i7-4771 CPU, 4 core, 8 logical processors, SMBIOS Amer. Megatrend version 2.7, avail phys. mem 28.2Gb, available virtual mem. 32 Gb.