I just purchased a GTX 460 to replace my old GT 8800, now I have both cards in my system, with the 460 as the main card and the 8800 dedicated to PhysX computing. For my processor I have a Intel Core 2 Quad running at 2.40 GHz.
and 4 GB of memory at 400 MHz each. By the way, this is a Dell XPS 630i.
With this I am getting sufficient performance, but I would like to push it up another notch, especially if I ever want to do 3D gaming in the future. So my question is, what should I upgrade next? These days 4GB of memory isn't much, so I was thinking I should add to that, but I also want to upgrade to an i7 at ~3 to 3.33 GHz, and maybe add another 460 and go SLI and scrap the 8800. I'm not made of money, so I can't do all of these at once, so what do you think will increase the performance the most.
The I7 is not compatible with your motherboard so that would be a full system upgrade. If you have overclocking possibility in BIOS (most Dell's don't) then that would be some free performance. Upgrading from 4GB ram to 8GB is not going to be a noticeable upgrade unless you are doing 3D modeling or heavy rendering where the extra ram is needed. Leaves us with GTX460 for SLI which you will benefit from if running on high resolution monitor.
4GB of memory is fine for the moment if your primary purpose is gaming. Considering your other hardware, I would start saving until you have enough money for a new build, as in order to change your motherboard you would have to get new RAM and a processor as well. Same goes if you were to get a new processor. I suggest saving your money and then building a new computer in the future.
If you replaced your motherboard with a newer one, you would need to upgrade the processor and RAM. If you decided to go with AMD the costs would not be that high, but with Intel it could be a little pricey. whats your budget?
I always use intel, so it may be expensive, because I want an i7. For my budget, I can't give an exact number but if I was only doing this to get an i7 I would say ~$400 - 500 tops. Though if I was to decide to get a whole new build I would be willing to spend a lot more.