FPS problem, but only online (BF:BC 2)

I get good smooth gameplay in the campaign, but as soon as I go online. I get terrible fps spikes. If I turn CF off, it solves it, but it sort of defeats the purpose of CF if you can't even use it. First, a couple of things. I use the latest drivers as of yesterday for my GPU's. They are 6950's with 70 bios. They are slightly OC'd (880/1400) but temps are good, and I'm having no issues in any other game what so ever, which i guess rules out hardware problems? Ping is excellent (around 15 on most server i play on), and it doesn't seem to matter if enter an empty one or a full on. Just being online is enough to kill the fps.

Anyway, as I first enter the server I will get some massive stutters when chosing gear.
I click to spawn and ig et even more massive lag. As it stabilizes at around 80 fps, i need to start playing right? Except everytime i turn i get massive drops in fps.

I can usually figure these things out, but now I feel I've tried everything google could turn up, and need some serious help

I would provide DxDiag and everything, but the game runs just fine in SP, even WITH crossfire enabled. but for some reason it doesn't online, regardless of ping, amount of players etc. It's not a matter of a low spec PC. That I do know.

edit/ I'm gonna open up some ports. Just because it shouldn't work makes me think it will.

I think it's off already, but i'll check just in case. Opening the ports obviously did nothing
And after playing for about a minute the FPS actually stabilizes, but is still LOWER than with CF disabled. I'll check HT next.

It didn't. And it was off to begin with, but just to be safe i reset the bios settings except HT and some other essentials like boot priority. Same thing. But how on earth does it only affect online play? That's what i can't get my head around.

edit/ I'm gonna try these http://forums.guru3d.com/showthread.php?p=3977545
Heard they were good for BC2.

edit/ Well that didn't do anything. Maybe the game just hates crossfire..

I installed RadeonPro, and it seems they cards are only being 20% used at best.

I'll try updating the bios. With Asus's EZ Flash system there is virtually nothing that can go wrong with trying anyway. Not that I think it will help, but i saw there was an update from around the time i stopped playing last year. I'll give it a go. Be back in like ten with the results.

No difference really. The laggy start is still there. Getting 60fps+ (70-100 usually) after it stabilzes on the Heavy Metal map though, so I guess it's not so bad. It might be placebo effect or whatever, but it does seem to stabliize a few seconds faster now.

My FPS stabilizes after some time. Choosing 'home theatre' sound some times make it not to hang. Also i found graphics settings and sound settings don't really make a big difference in my fps. It's about the same irrespective of settings. Which is kind of weird.

What I dont get is that ALL other games works flawlessly. So can it be a bad OC? Probably not.
Drivers? Well it works great in SP.. I'm really quite confused. A friend of mine with i7 and and old 4xxx series get's more fps than me :/

I'll look into.

edit/ I could not find such an option.