I have had that video card on one of my laptops.
And definitely go with the ram if you can, but don't buy it from dell, buy it online for 1/4 the cost. Installing it is pretty easy if you follow the instructions in the Manuel.
It is a great video card, under vista 64/32 you get about the same frame rate. around 16-20fps or so.
If you get XP it will run much faster.
Under either though you can raid no problem really and pvp, the framerate will be between 10-14 though just to warn you. But Ive raided successfully with less in molten core lol
The real big difference game wise for me between vista 64/32 and XP 32 was random lockup /freezes crashes.
XP 32 random crashes in alot of games/ sound glitches / crashes that were unrecoverable when running new buggy gaming software.
Vista 32 crashes, but not as hard as xp most of the time you can get back to the desktop at least. Slower gaming performance but better crash protection was nice.
Vista 64 Almost never crash out so hard you cant get back to the desktop. less sound glitching in new games (unpatched, brand new you are the beta tester fun) Less crashing the OS in general. In fact even with all the buggy beta software I run for testing, I havent crashed the OS in a month. Usually under XP I crash it a few times a day.
XP is faster graphically, it may be that the drivers
are written better, there is less overhead or the hardware itself is just more happy with xp.
As a side note: The dell support team does not in any way or form like to support vista x64, when I originally got my vostro laptop they did, then they pulled the support for it and all the drivers from the website. I have to use the XPS X64 drivers for my vostro now its the only way I can get the chipset drivers to work right.