Hey Unacomn, I know you've said you're running on a system that's way under specs earlier in the thread. Some of the performance problems you've mentioned though remind me suspiciously of some of the problems I was having before I did the "Speaker Output Fix" that's talked about on the official forums. Do me a favor to save my curiosity (and maybe fix some of your performance issues) and set your soundcard/speaker output to 24 bit, 48000 Hz and see if this fixes some of your issues. If it does seem to magically fix things for you then you might even be able to try to set some of your other settings up a bit higher and see what happens.
Just so I don't go insane wondering let me know if that helps you out any or if maybe you've even already seen it on the forums and tried it.
Windows XP won't let me change the setting in that way, but I have tried every option in the compression and hardware acceleration sliders, with no effect. I was pleasantly surprised that the sound ran normally actually, in New Vegas it was a complete mess.
Sound isn't really the issue for my PC. In interiors it gets up to a very high framerate, it's the loading of textures and map data in the outside world that causes the game to slow to a crawl frequently. That and the processor can't take a lot of things happening at the same time on screen.
Still, it looks very good considering it's running at about a third of the recommended RAM and half the CPU