Here's screenshot of System Profiler so you know what I'm talking about.

The card isn't patched, so I actually have no idea how it recognizes 512 MB memory. As you see I use NVinject and I have QuartzGL and Dual screen working.
The problem is that 3d accelation is very slow. And graphical programs (and I believe games) hangs with different memory access errors (for example EXC_BAD_ACCESS). Also some applications simply doesn't work as intended, for example Front Row just makes screen black and prevents any interaction unless I exit it by pressing Esc.
I've searched the Internet for a while and so far haven't found anything but some outdate resources which didn't really help.
Is there anything I could do to make my card fully working? I'm very happy with my current install and only if I could get my card working, I could switch to Mac as main OS.
Any Tips/Ideas? Any help would be really appreciated!