Upgading Geforce 7900 GS-OC

Current Build:
Gigabyte p35-DS3L MB
Core2 Q6700 CPU
2x2GB G-Skill PC2-8500 1066MHZ RAM
FoxConn Geforce 7900 GS-OC 256MB (factory overclocked, 3dmark scores ~7900 GT)
24" Dell LCD (1920x1200 resolution)

Usage:
I play mostly RPG games (Civ4Colonizations, Age of the Empires 3), but I also play some Madden/Battlefield 2/TrackManiaNations, and I'm interested in playing CoD4. I like to game at 1920x1200.

My current GPU allows me to play at high resolutions with medium to high settings. AoE3 and Madden 08 do get bogged down...framerates drop to 19-24 fps on those games on medium, and high settings are unplayable.

Question:
What kind of video card upgrade can I get for $100? And how much will it help?

That is a great card....but it's more than I wanted to spend. I guess I can spend the extra $30, but I wonder if it's more than I need. Most of the games I play now play just fine with my current card, and I'm wondering if the 256MB of vRAM is hurting me on the games that are bogging down. I guess I'm wondering:

a) Would simply having more graphics memory help my current situation?
b) If more v-memory will make things better, how much do I need to upgrade the actual GPU? 7900 GS to 8800? HD4830?

I guess I'm wondering: "If I had 512MB of vRAM, would my 7900 might work just fine?"

Obviously, if I need to upgrade the vRAM, I have to buy a new card. I'd LOVE to buy the latest and greatest, but I'm on a tight budget these days. I'm seeing HD4670s and Geforce 9600GTs for around $70 plus rebates. Do they offer better performance than a 7900GT with the increased 512 RAM? Or do I need to bite the bullet and spend $100-130 and get an HD 4850 or GT 250?

Have a look here. it`ll give you a idea as to where each card stands.

http://www.tomshardware.co.uk/gefo [...] 515-6.html

If you want to play FPS shooters like COD4 I would really strongly advise you to look at getting the fastest card you can afford.
That said the Egg has a pair of HD4830s for a little over $70 with rebates, which is faster than the 9600GT although slower than either the 9800GTX/GTS250/Hd4850.
Take a look here for a few performance numbers.

http://www.techpowerup.com/reviews [...] _250_1_GB/

I`d suggest the slightly slower 9600GT, it`ll save problems with driver installation.

I looked at the chart already. But there isn't hard data for that chart. It doesn't give me a % improvement....it just says "This group of cards is better than the next group". I can't find a straight Geforce 7900 vs. geforce 9600 GT or HD 4830/50. That is why I said "it look like a 9600 GT or a HD4830 is 3-4 tiers better".

I also had asked people about that sapphire HD4830. Thanks for seconding that card. Anyone else got an opinon on which card would be a good upgrade?

Go with that Sapphire 4830.

SAPPHIRE 100265HDMI Radeon HD 4830 512MB $89.99
http://www.newegg.com/Product/Prod [...] 6814102822

Sapphires custom PCB uses a little less power than the reference design, and it's a pretty good card. It will prove faster than the 9600GT, especially if you overclock the core a bit. If you can wait till tomarrow though the 4770s should be comming out soon for under $100 and they offer better performance than the 4830s, almost the level of the 4850s.