I've been using player.fullactorcopy a lot of times on a friend's rig to raise the ram usage over the 1.8Gb limit but doing so the triangle count skyrockets to over 9 millions, the game is nearly unplayable that way and whenever it crashes I don't know if it's due to an overload CTD or to the LAA patch not working as intended. Any ideas on how to quickly raise the ram usage without bringing the system to its knees?

Last statement is an oxymoron. Raising the ram usage too high will bring the system to it's knees, unless you have an abundance of RAM. I don't think there is a console command, and anything that you add to the game to use more RAM will also strain either the GPU or CPU.

dAb - What you were doing is probably already one of the better ways. Just keep your resource monitor open, and if you crash immediately on passing 1.8gb ram, you know it's the ram limit. However, I've never heard of LAA patching not working in the technical sense. It may not solve particular problems, but certainly if you've run an LAA patcher on your Oblivion executable, then it's patched. What are you using to do it? I recommend CFF explorer, since you can go through and verify afterward that the change stuck.

Yes, I've been using CFF explorer to patch the game exe. Worked like a charm on my end but I can't tell it's working in-game on my friend's computer because of the consistent crash she gets whenever the triangles count exceeds a certain amount. Given the fact that it might be due to a gpu overload I was basically looking for a way to force a system memory leak via console, which as far as I know doesn't strain the gpu at all, and was hoping for a known game flaw to do that. I remember of a buggy mod which slowly caused a memory leak in Anvil but I can't find it anywhere as I can't remember its name.

If you're using CFF explorer, you can check to make sure the change "stuck"... If it did, there's no real possibility that Oblivion is still somehow holding at it's normal 32-bit ram limit, although of course depending on the system specs and OS your friend has, you may be getting almost no additional usable ram. Nor would there be anything else you can actively do that wouldn't involve a hardware upgrade, at that point.

If it's a graphics problem, though... have you checked for driver updates?