I've tried the volume frequency thing, it did fix the crashes for me when the game got released but now it doesn't work anymore.
I've tried editing the exe file to allow 2gig of ram usage(i think that's what i did)
i've tried setting all graphics down to absolute worst(i have better than recommended specs for ultra)

Please someone give me some tips, i just got dawnguard and I can't play like this.
I crash anywhere between 10 minutes and 2 hours. no pattern just randomly, menu screen, combat or just nothing, so it's just random.
pls help

If this only happens with Dawnguard installed, you posted this in the wrong forum. There is a seaparate Dawnguard Tech Discussion Forum.

This has happened for like 4 months now, just came back from a break which i took because of the game crashing, forgot that it kept crashing, bought dawnguard and crashed in like 10 minutes.
Dawnguard most likely has nothing to do with this, since it's exactly the same like it was before dawnguard came out

You will need to provide the diagnosticians here with the correct complete information if you hope for a useful answer.