I suggest a GTX 460 if you can afford it and Nvidia is to your taste, the 5770 is a ok card as well if you are looking for something different. However if you are one of those who are either very cheap or broke like me most of the time a cheap 9800gt will blow your current 7900gt away. I had three 7900gs and still have two 7900gtx duos along side with two 9800gt so I know how well they perform.
type of ram doesn't matter, a card can have ddr2 3..5 it doesn't matter the type on the graphics card as long as your psu can handle the power needs of the system and the card, and provided you have a pci-e slot (you mentioned askign if you go by the pci-e 2.1 x 16 so as long as you have that on your board this part is good) you'll be fine
and I am not sure what my max ram would be on this motherboard do you?
I guess if the motherboard has DDR2 on it you cant put in DDR3
but with the video card you can use the faster DDR3 or 5.
also would it be better to up grade with a new MBoard and go ddr3
if so what Mboard intell I5 or amd?
oh yea still looking for the best video card under $150 Also see the price of the older 5mb cards coming down in price should I get one of those?
I know it is not a up grade but I don't run games my son does I but I could use a card with HDMI out .