How many frame rates would I lose with P45 chispet

hi I m planning to crossfire my system but I have a few issues these are my chipset first of, how much frame rates have been lost..

also I fear my HD4870 512 has not got he power for what I want it to do

my current mobo is P45 maxumus 2 formular
my GPU is HD4870 512
Q6600 @3.61Ghz
and my power supply uni is 1100watt Tagan piper rock

any help would be nice thanks

and marry xmas

yes I should do, however, compare a X48 chipset to a P45 chipset in crossfire, same card same CPU and everything exect the mobo. how many frame rates would the P45 chipset based comp lose verses the x48 that was my question

asuming my mobo is working properly in the first place which I deailt(been acting funny racently)

I could do, I do have the money for one but thats not the first of my problems, I trhink my mobo acturly is damaged A. its unstable no matter what I do :| it crashes in game the error code relating to the BIOS, ive agusted the voltage a little still nothing it does work through.

2. £400 for a card is a little over the top and my country is suffering to the credit crunch vairly badly
is a X2 a little overkill ?? I don't game at very very high res with 8x AA otherwise i would have by now

and I don't know if OCUK would cover it for RMA the mobo cos, if it is indeed damaged, it was probley done by a fatuly powersupply unit, its never been the same since, since it was working properly before hand i don't know if they would take it back.