I'm primarily upgrading my computer to play games with. I have a ATI Radeon 4870 512MB video card, and my monitor only supports 1680x1050 resolution so obviously I don't need as much graphics muscle as some people would. I currently have a Core 2 E6600 running on a low-end Gigabyte 965P Intel chipset with fairly low-end OCZ 800 DDR2 memory. Unfortunately I can't overclock this system very high due to the low-end motherboard and memory.
AMD Phenom II X4 940
CORSAIR DOMINATOR 4GB 1066 DDR2 5-5-5-15
Another ATI Radeon 4870 512MB
So my question is, for 1680x1050 gaming, would I be better off going with the Phenom II and having less CPU power but having greater graphics power, or should I get the Core i7 and have higher CPU power but lower graphics power (at least for a while, I could still add a second 4870 but it would take at least 4-6 months)?
I don't really want the onboard graphics, it just seems to come on all the 790GX motherboards that I looked at. If there's another option in the same price range that's as good and doesn't have the onboard graphics then that would be fine with me too.
Oh, and I live in the US so the difference in cost between the platforms is only about $150, and my monitor is fairly new so I'm perfectly happy with having a 22" monitor. So the only question is whether I should spend the funds on a second video card or a better processor, keeping in mind my fairly modest resolution setting of 1680x1050.
I agree with tahmid. If you only want strictly gaming, the difference between Phenom II and Core i7 is not worth the $150 bucks. On the other hand, I recommend 790FX chipset more, because in case you want to upgrade, you can just pop another 4870 in there for Xfire, without having to buy brand new graphic cards, and cost you less in the long run. I also agree with the 4870, as they're excellent in terms of performance / $. However keep in mind that 4870 is really really really loud under gaming, so you might want to find a non-reference 4870 (like ASUS's Matrix or DK series).
With that being said, this is my recommended set up.
AMD Phenom II X4 940 BE
ASUS M4A79T Deluxe
4Gb (2x2) OCZ DDR3-1600 CL8
ASUS 4870 DK