Too much, or not enough?

I recently built a new pc for myself.

Antec p183 case
Sigma monster 750W psu
AMD Phenom II X3 @ 3GHz
4gb of ddr2 memory
Ati 4850 1gb by XFX
160 gb hd with windows 7, 1TB for data


My question is, if I upgrade to a 5850 or 5870, and "maybe" do crossfire later on, would the cards be limited due to my cpu not being an extreme clocked quad core processor. Because after these insanely amazing cards came out, I'm about to sell my other pc, just to get one. Would it be worth the upgrade? I play games at 1440x900 on a 19inch widescreen monitor. I plan on upgrading to a 24inch in a month or so. Also, I know playing at that res I won't NEED crossfire BUT I just want the extra processing power of that added card. Just let me know your opinions.

I'm thinking in a few months, ill see about building an intel rig, but I've always owned amd powered pcs. Plus, I kinda support amd more, cuz I've read a lot of bad things about intel trying to stay ahead of amd, by bribing them, and I'm not sure if id support a company that does that. Anyway, that's beside the point, I just want your personal experienced opinions on either issue.

Thanks for any help guys

Alrighty, cuz with my cpu, and 4850, I actually get 70 avg fps with fallout 3 max everything at 1440x900. The lowest its dipped down to was 35 fps when a lot was happening on screen. I asked about that whole intel thing because I might do a core i7 rig with 5850s in crossfire. But I don't care for intel, cuz their always changing everything around. And priceerformance ratio is really bad with intel. So I might wait for amds so called opticore and octicore processors to come out, or ill just upgrade my PII x3 to a 965BE.

I honestly couldn't tell you if it'd fit in your case. Since you have the case handy, try taking a tape measure to it .

As for Fallout 3, if you upgraded the GPU, you'd definitely get rid of the stuttering with a GPU upgrade. Since all the 4000's are on the cheap with the 5000's out, have you though about grabbing another 4850? They're going for about $100 each depending on the brand. If you did upgrade your AMD CPU, I honestly don't think you'll see much gain at the resolution your playing at. CPU limits really only show up when the GPU is still flying and asking for more. You could get higher than 70 fps with a faster CPU, but since you're over 60 fps I don't see how it would matter.

I'm using an i7 for my gaming rig, and and Phenom II in my HTPC. The intel i7 920 chip is cheap right now, but you pay a lot more for a quality MB and DDR3 RAM to go with it. I'm happy with both of mine, since they do the job I bought them to do.