Upgrading my Formula IV, 965BE rig

[snowjunki]

Hello,
I've got the Crosshair Formula IV, 965 BE cpu and a 750W Corsair PSU.
I currently am running a 460GTX (MSI frozr), and want to upgrade to a crossfire ATI setup.

Really, I'm willing to throw money at any card model range that will get me the best performance out of my mobo+cpu setup. I'll be upgrading from my 4gb Gskill to an 8gb 2 x 4gb if that will net me the best performance in conjunction with my 965BE oc'd upwards to 4.0ghz. Really, it's my mobo that is the bottleneck constraint on the rest of the upgrading possibilities.

I am also willing to upgrade my CPU if AM3+ support (beta BIOS) on my Crosshair Formula IV will see the desired performance increase.

PS, I like MSI gpu's for the obvious reasons but am open to whatever suggestions you have. At this point I don't want to be buying 'ran-through' gpus that are 'refurbished' status or returns. Hoping for advice on the best crossfire setup that will take my mobo and amd cpu to their max. I pieced my rig in 2010 with the intention of upgrading it to it's maximum potential. This includes the possibility of updating my BIOS to support an AM3+ cpu if it will return the performance.

 

[swifty_morgan]

don't crossfire 2 low/mid-range cards. don't crossfire 2 - 1gig cards. better to buy one single beast..............

 

[snowjunki]

Okay, I can dig that. To clarify, I wouldn't be buying two GPU's right away, but with plans to crossfire the cars down the road.

I'm interested in the MSI Hawk HD7870. With this card, am I overstepping my system's abilities? The big thing I'm worried about is my mobo's ability to run 2 x 16x with a PCI-E 3.0 GPU setup.

The cpu situation is what I'm most unclear about, in terms of upgrading to another AMD option. I don't need 6 cores and if I were to get a new CPU it would be an AM3+
Does anyone have any experience with the Crosshair mobo and AM3+ compatibility with the new BIOS?

I'm running a coolermaster scout case that has ample airflow in its stock form, and I'd be willing to get creative with an aircooling setup that really gets the breezeway going.