Will the Intel i3-3220 3.3ghz coupled with an AMD radeon HD 6850 be able to run WoW on ultra with acceptable FPS in 10man raids?
Yes. You might not get a full 60 FPS but, it's more than capable of running it at 50+
I run it on high at 60 FPS with a ATI Mobility Radeon 5730 and an I7 M-620 at 2.6ghz at a solid 60 FPS, I just don't care about the looks enough to bump to higher graphic settings.
I3 might be what's bottle necking you here, two cores isn't amazing but if it's only 10 man, you should be good.
i dont believe wow uses more then 2 cores currently, for a budget setup this will work fine. though there may be a better card available for the price of a 6850 if you are buying now.
i just did a google search and it looks like they are around 150$ still, and i know microcenter is selling gtx 570s for 150$ if you are lucky enough to live by one, but either way deals on last generations cards are all over, but to your original question that setup will handle 10m at ultra nicely, maybe shadows turned down a notch.
Intel i5-2500k@4.4ghz
Gigabyte Z68X-UD3H-B3
Gigabyte N560OC 1gb gpu
Corsair 2x4gb
Antec v2 Two Hundred
Razer Blackwidow Ultimate
Razer Naga
Well, then don't think and look it up. Wow Uses 3 main threads and a few smaller threads, so any quadcore will trump a dualcore in WoW. Beyond quad only cache memory will add extra performance, and clockspeed offcourse. However, the i3-3220 has HT, so it'll be fine. Long as you dont push the settings, and be a little easy on the recount-style-mods it should be just fine.
The keyword you have given us is 10man, which should be ok, but don't expect to be running on full ultra, unless you're playing on really low monitor resolutions.
Minimum fps doesn't deteriorate on lower resolution. It just caps out. Like for example playing with a i3-3220 in combination with a GTX690. Then the framerate would be identical on 800x600 and at 1920x1080 because the minimum/averate framerate would be determined by the processor speed. Maximum framerate could fluctuate depending on the performance of the GPU.