(posted this before in some other thread, sorry for "spam")
I finally managed to (properly) test it now and was was able to play for hours and hours at maxed details, singleplayer as well as multiplayer, without any crashes, texture bugs or stuttering.
-maxmem=256 (512 will still crash the game for me) and >2gb addresstest seem to work. We applied the same solution to a friend's ArmA version (1.08) with the same stable results.
This seems to work for me also.
Haven't tested 512mb yet, but my graphicscard only has 256mb or is that number referring to your system memory? I have 4096mb system memory, so I don't think I'm short on that