[quote name='Slim Gatsby']Thanks! So, sticking with this one for $50 should work out, then? What is so bad about the GDDR3?
I'm definitely thinking about rebuilding one in the future. The system I have now is the first system I've had in a decade that I haven't built myself; I've just fallen a bit behind since I haven't had the time or inclination to follow it in a while.
Would I later be able to get a second one of these for crossfire, if I need it later on?[/QUOTE]GDDR3 is the third generation of video RAM for video cards, while GDDR5 is the fifth generation video RAM. GDDR5 is going to be faster for a video card than GDDR3, and I think it has a wider memory path as well.
Since you're running on an Athlon X2 5000+, the differences you'd see between the GDDR3 and GDDR5 versions of the card wouldn't be anything you'd see. On a newer system, you might see some of it, yes.
I think that building your own would be something you should look at, as an investment of $600 - $700 will get you a system that will kick the doors of what you currently have.
The current system won't have enough PSU to drive anything that requires supplemental power to the video card, as I stated above, so I think the card you picked out will work just fine for the money you want to throw at it.
Don't even think about a second card for your system, even another card like the one you bought. Your system won't have enough power to drive a second card, and you'll be hitting CPU bounds more than video card bounds from what I'd think. Save that thought for a future system you'd build on your own.