4870X2 and 4870 crossfire issues

[zlojack]

i have a 4870 x2 in Crossfire with one 4870 512 MB that combination is something like a X3 (3 gpu's) (both Powercolor), and it works great... only window Vista (my version, ultimate 64) can recognize 3 GPU's, windows XP is useless, only recognizes one or 2 GPU. (yes, i have both OS in my computer) all i had to do is install the 4870 x2 first, install drivers, then plug the 4870 and reinstall everything, if your really lucky, this process wont be necessary, windows will recognize the 4870 512 mb and allow you to do crossfire as soon as you restart the machine.

Given some rumors i must confirm that if you crossfire 4870 x2, with 2GB per GPU with one 4870 512 MB per GPU, Catalyst will automatically use only 512 MB per GPU wich in my case only use 1500 MB os memory.

i hope my comment helped some of you, thkx

(by the way english is not my 1st laguage)

Interesting.

Do you have benchmarks with those two? What's the difference with the extra card?

[BulletProof]

there is definitely an improvement... in 3d Mark06 with only one 4870 512 MB i get a result of 16.750... in crossfire, with the 4870 x2 and the 4870 512 MB working together i get 22.834, so there is a big difference, jumping from the x2 alone to the crossfire setup i dont see as much improvement, it's like from 20.650 to 22.834, but in some games that percentage still makes all the difference (yes Crysis, i'm looking at you)
the Crossfire technologie is, as far as my experience goes, very stable nowday's... just dont go out and buy two 4870 x2 to quad Xfire, waste of money, 3GPU is a more stable solution, and better investment.

By the way i noticed that this GraphicCard's have too much power and can be severely bottle neck due to weak CPU's... if you buy one of this please buy at least a Q9550 and overclock him to something like 3.8/3.9... in that case, you will see a monter that can play everything even crysis at 1900x1200 very high 2x antialising with no problems whatsoever, otherwise, if you have a weak CPU clocked at 2.66 or 3.0, you will be bottlenecking this GC and wont get anywhere near that performance... the chart above doesen't show the true power of this cards, they benefit like no other from a fast CPU.

My system is:

Rampage Formula / 4870 x2 in crossfire with 4870 512Mb / q9450 overclocked (3.68Ghz) / 6Gb DDR21066.