Possible to Crossfire 4870 and 4850?

Hi All,
After a strange series of events with UPS and Newegg, I've ended up with two GPUs: a Visiontek 4870 and a Asus 4850.

I've got the 4870 in my rig now and I'm loving it. Is it possible and/or logical to add in the 4850 for Crossfire? Will I see any gains?

I usually play at 1680 x 1050 resolution.

Here are my system specs:

Q6600 at 3.4Ghz
Asus P45Q
4GB Ram
750W PSU
Vista 64-bit


Thanks.

Actually CFing a 4870 and a 4850 will severely limit the 4870 so that it will be like CFing 2 4850s.

Might as well just sell your 4850 and add another 4870 if you need.

Rangers is correct and so is Kingtz. Crossfiring a 4870 and a 4850 is going to bring the 4870 down to function as a 4850 BUT this is still to your advantage as 2 4850's easily beat out 1 4870....and its costing you nothing...