If you're plumbing for the latest, hot-snotting 3D beast, with as much RAM as possible, be prepared to encounter some additional problems, if you don't have enough system and virtual RAM to back it up with. Without going into all of the gory details, one needs to remember that rendering data is copied across from the system memory, not "cut n pasted". So a game that's using 300MB of video memory, just for things like texture buffers, is going to take that slice out of your system memory too. For 32 bit operating systems, there's also a limit to how much virtual memory a game can have, and there are many cases where a graphics card using lots of VRAM can eat into this limit so much, that it causes the game to run badly and even crash. Sometimes this can be fixed with patches, but for real solution to this, for the future, is to have a 64 bit operating system.