I just upgraded my PC with an AMD 940 x4 Phenom processor and a ATI Radeon 4870 Graphics card to run 3d applications faster.
Though when I run Maya 2009 in a scene containing 14046 faces, it's still quite laggy. Could it be due to my silly 2gb of ram?
I hope it is, because I was expecting more performance improvement by doing such a radical upgrade.
You really should have a professinoal card if you want to do any serious work in maya. The gaming cards are not designed to do that sort of work, and do it very poorly.
While im sure more ram wuold increase the performance in an application like this the 4870 is anything but optimized for it. If this is a hobby you can probably get by with a bit more ram and take th slow performance. If it is for work you really should invest in something far more robust.
Regardless of your system a 4870 is never going to run maya et al anywhere close to even a lesser professional card. Of course a lesser professional card won't run games well/at all...