Hi there. I've recently purchased Fallout 3 GOTY from steam, and am suffering issue after issue with it, it seems

After finding out i needed GFWL to run it i've managed to get the game running, however the game freezes constantly, sometimes in little over a minute of gameplay.

Details:

My pc is running windows 8 Professional edition.
I've got the Intel Core I7-2600 Processor
8GB of memory
AMD Radeon HD 6700 graphics card.


Freezes are ocurring often during "instances" where actions are occuring (eg. leaving/entering an area, activating switches & firing guns)

Freezes were locking my computer entirely and needing a force restart in fullscreen mode, however by playing in windowed mode the program usually froze but allowed me to force a close via task manager.

attempted fixes so far: (note: these are not necessarily in order)

Updating to latest graphics card drivers.
Running Bethesda 1.7 official patch off the website (just in case steam wasn't up to date)
Running the unnoficial fallout patch mod. (after reading a suggestion about general bugfixing on this forum somewhere)
Changing fallout.exe affinity to just 1 or 2 cores. (as suggested online)
Changing graphics quality from Ultra to Low (this has slowed down the number of crashes, but they're still happening around every 10 minutes)
Modding the .exe to allow running more than 2gb of memory (as suggested online)
Modifying the .ini file 2 limit game to using 2 cores. (as suggested online)
Disconnecting all the DLC that came with the game.
Running game in compatibility mode set to: windows 7, windows vista, windows XP (servicepack 3)
and ofc running the game as an administrator.


It's been a fair few hours into researching/modding/testing now just trying to get this game to work and honestly i'm starting to despair. I feel like I've tried every fix suggestion on the internet (and combinations of them, too) but the game is pretty much unplayable at this stage.

any help would be greatly appreciated.

(note, also I can post a dxdiag if necessary)