4870 cf issues

after finally splashing out and treating myself to what I would have thought would be close to the best gpu set up money can buy atm I have been nothing but miserably disappointed.

For the ridiculous sum of $1200 NZ I got 2 ASUS 1gb dark knight edition 4870's from the states. After finally getting crossfire working on ATI's 8.11 drivers (8.12 didnt work as every time I tried to enable CF windows tells me one of my gpus has been disabled due to driver incapability) I have not been particularly impressed. performance in crysis actually dropped and my 3dmark 06 score increased by maybe 1000 points at most.

So I have a couple of questions:

First can an insufficient psu lead to poor performance? I am not getting any random lock ups, crash to desktops or bsods or anything of the like but currently I am only running a 600w thermaltake tough power psu which I thought would not come close to cutting it for both of these cards but as I am waiting for my 1200w psu to arrive I thought I would just try them both out on my 600w one.

Secondly I am only running a e6550 at 3.2ghz, could this be what is bottlenecking my system? I held off on upgrading my cpu as I thought the money would be better spent on a new gpu(s).

specs are:
vista 64bit
4gb super talent dd2 ram
x-fi fatality sound card
2x asus 4870 1gb gpu's
3x 500gb hdd's
Asus p5k C mobo (and yes it does have 2 x16 pcie slots)

I think thats about it, thanks for any help

Something's definitely not right - I have a 4870x2, and I got nearly double the performance when crossfire was working as compared to when it wasn't in Crysis. 3dmark should have had a hefty bump as well.

I'm sorry but i'm going to make a very unconstructive point. Look at gpu forums everywhere. They are full of ppl asking for help with CF/SLI. The reason why is that it simply doesnt work well enough. Which is why I would currently never recomend it to anyone.

D3LTA09 theoretically you should have a 100% improvement but it simply doesn't work like that. TBH at best even if it was working you would likely see an improvement of approx 30%. So instead of 40fps you would get approx 50fps.

It does appear that your are getting extremely good fps out of 1 card. I would be very happy with those results personaly.