Sorry, this just isn't accurate. The patch you installed might have done something to fix your problem, but it was not related to the amount of VRAM you had unless perhaps one of your cards has bad VRAM.
I have 8 GB of RAM and a GF 8800GTS 512 MB card, and have the exact problem as the original poster. Add the -winxp switch to the shortcut (so it reads arma2.exe -winxp or something similar, for example) and it should fix the problem. Once I launched with that switch, the graphics were fine and I was able to crank everything up to high/very high (including textures) and had no problems.
I've read that this switch emulates having 4 GB of RAM, though I am not 100% sure what it does. All I know is that I researched the problem, found the switch mentioned as a possible solution, and can confirm it works.