Most likely due to a 32MB *SHARED/SYSTEM* graphics card (ie. a built-in one, that pulls memory from RAM to power itself).

As an example, Battlefield 2 plays good with 1GB of fast RAM (ie. DDR or DDR2), but plays a LOT better with 2GB (faster load-times, smoother in-game, etc).

As for a graphics cards, look for the number of pipelines it has before you look at the amount of memory it has. From memory (and I only know the nVidia cards because that's all I use), the 6600 range has 8 pipelines, the 6800GS has 12, the 6800GT has 16, all the way up to the brand-new 7950 GX2 which has 48. Not sure which I'd choose out of a 512MB card with 12 pipelines (the relatively newer 6800GS) or the currently-being-used 256MB card with 16 pipelines (the slightly older, but still more expensive, 6800GT), because I've not tested both side-by-side.

All-in-all, I'd say it depends on your budget......my next gaming-rig currently has a shopping list of just under £1,400 (not counting a monitor, since I already have decent one). That's spec'd with a £390 PCi-E 512MB XFX nVidia 7900GTX "XXX edition" graphics card that's just been reduced in price from £499.

I tend to get most of my stuff from Scan Computers, in Bolton (just behind the Reebok Stadium, for anyone nearby), but have recently started buying the odd thing from MicroDirect, in Manchester, as they're a bit cheaper than Scan for a few things and are about the same distance away from where I live.