replacing old gpu

I have a P5ne sli mobo with 2 8500gts, and a q6600 processor. My psu is 600 watt and also have 4 gigs of DDR (upgrading ram soon as well) running XP pro. Dell E248WFP 24'' Widescreen LCD Monitor

This setup is plenty for GW but I would like to be able to play STALKER Shadow of Chernobyl or Clear Sky on max settings( minus the dx10 stuff since I'm not going vista for awhile) but my current cards are not up to the task by a mile or so (medium textures and static lighting at 1024x768 instead of my monitors 1920x1200 native res, stop errors when i try).
Don't need to get 2 right now as i believe 1 8800 gt would be an improvement but would like the option to buy a second card as long as it would be even better than having only one.
I am not going to overclock anything because I'm not rich and can't afford mistakes . I am willing to spend up to $500 on EACH card (2nd card to be purchased later).

I kinda know what I'm doing but am apprehensive about purchasing anything without advice because of all the different variants and manufacturers out there.

I was thinking about a evga 280gtx 1g, what do you guys think?

Hope I gave enough info to help you help me :P

Thank You.

Yes, the GTX280 will suffice very nicely, especially with the amount you are willing to spend. However, a 600watt PSU is going to be pushing it. 750w is what I would recommend considering you have a quad core and presumably 2+ HDDs. I would highly recommend doing a SLi GTX260 revb (216 SP version) setup. This will allow you to purchase a new power supply as well as the first card together, and the second card later if you desire.

Your best bet would be to do this;

GPU: http://www.newegg.com/Product/Produc...82E16814130398

PSU: http://www.newegg.com/Product/Produc...82E16817139006

Hope that helps.

Note that WinXP Pro can only access 4 gigs of RAM, so upgrading to more RAM won't work unless you upgrade to a 64-bit OS.

Other than that, I agree with Rahja on the video cards, since you are already running nVidia SLI.

Yah i know, was just gonna get better faster stronger ram since mine is generic.

What brand is your PSU?
-If its generic you will need a new one. The Corsair Rahja suggested is suitable.
-If its a good brand you can keep it.

What speed is your RAM?
-There is no reason to upgrade if it is 533Mhz or higher since you will be running your CPU at stock speeds. The FSB of a Q6600 is 266 (quad pumped) so 533 RAM or higher is fine. Having a FSB:DRAM ratio of higher than 1:1 isn't really necessary as the FSB architecture does not utilise the memory bandwidth offered by high speed DDR2.
-Even though its generic, if it has no errors than just leave it. The money can be better spent on other components.

Personally I would get a single GTX260 Core216/Maxcore/rev b and when you need a second consider another motherboard. That P5Ne SLI motherboard has a sub par chipset and doesn't even have 2 PCI-E x 16 lanes. By the time you need another GTX260, motherboards based on the 7x0i chipset will be cheaper anyway.