looking for crossfire 5870 but question

ok heres my hardware list
ASUS M4A785TD-V EVO AM3
AMD 955 oced to 3.8 stable
4gb ram G skill timing 9-9-9-24
Rosewill 750W 80+ certified
saphire Vapor-x 5870 1gb

since my board is 16x 4x
would it be worth crossfire on the 4x
id have to get rid of my PhysX card but i can get a new motherboard sooner or later that will support it but i was wondering would i bottleneck or anything i don have any idea about bottlenecking

or would i be better off to sell my GPU and get a 5970?

thanks

its not worth to crossfire if you have 4x-16x mobo.
You would get severe bottle neck and very small increase in crossfire.

Get at least an 8x-8x or 16x-16x. youd get 50%-60% increase at least but varies widely among games.
With 4x-16x you would get a maximum of about 20% increase in crossfire.

ya i was affraid of that i plan on getting crosshair sometime for have 16x 16x

if you are set on 5870 crossfire, you'd either want to upgrade your mobo or just get a 5970. I take it you are using multiple monitors/higher resolution that would benefit from more than 1 5870?

im planning on it but yes i know i need to upgrade im thinking of getting a new 890 chipset do the dual 5870 outperform the 5970?

5970 is basically 2 underclocked 5870s. 2 5870s should outperform 1 5970 at stock speeds.

I wanted to go crossfire as well but ive got the same issue x16/x4 slots. Ive also got a physx card in my rig and for the time being, I am happy w/ the performance of my 5870/8800gt. A 5970 is a good idea but Ive seen a couple of people here say they have been having issues w/ their 5970's. Seems to be a driver thing. I'd take that into consideration and do some research to see if its a minor issue w/ that card or a big one.