Ok let's say i have a machine with enough PCIx16 slots to support 2 full sized cards so let's take it from there .
I have a 5870 now what would happen if i buy a 5970 and hook them both up in crossfire.
Now 5970 is essentialy 5870 just 2 times but "underclocked to match 5850 because else they would exceed the power
border of 300W consumption for a videocard so it has been down clocked to 300W now from here.
IF i put my 5870 and a 5970 and than i take that 5970 i can return the original settings basicly overlocking it to reach the 5870 specifications and exceeding 300 WAT power which it has meant to do now if i do that wouldn't i than in theory have 3x5870 ?
I get what you are saying you want a setup like with the 4800 series where you could have a 4870x2 and a 4870 in 3 way kinda thing. I would think you would be ok by underclocking the 5870 or overclocking the 5970 or simply grab one of those new MSI Big Bang Motherboards with the Lucid chip and you can run a GTX 295 and a 5870 if you want. I would hit up www.game.amd.com forums and ask a moderator there.
I wouldn't assume you can overclock the 5970 to match a 5870. The 5970 uses close to 300 watts. The MB supplies 75, the 6 pin 75 and the 8 pin 150. Total is 300 watts. The more you overclock, the more power you need. I read that in the future, some 5970's will have 2x8 pin connections which will supply an extra 75 watts. This is what ATI had in mind for overclocking the 5970.
WEll if i hypothetically get the money for it i might as well the dillema here is not the card it self it's either 5870 or 5970 but yes eyefiniti would certanliy boost my capability's right ;P but problem is with eyefinity you have the ugly damn lines between each monitor which annoy the hell out of a person