My 5970 thinks it's card no1

[apoppin]

Do you mean install the graphics card while the commuters on? That can't be good...

NO!

Sometimes you will only get one card to install and the second one will not be recognized properly. Not your issue in this case.

First of all, you DO have a decent PSU, right? And both cards are seated properly with all of the (6-pin+6-pin/8-pin+6-pin) PCIe connections in tight at the card and also at the PSU, correct?

You should only have one CrossFire Interconnect Bridge installed.

 

[HAL9000]

NO!

Sometimes you will only get one card to install and the second one will not be recognized properly. Not your issue in this case.

First of all, you DO have a decent PSU, right? And both cards are seated properly with all of the (6-pin+6-pin/8-pin+6-pin) PCIe connections in tight at the card and also at the PSU, correct?

You should only have one CrossFire Interconnect Bridge installed.

Alas all of the above things are present and correct, my commuter won't boot with my 5870 in 4x no matter what I do, unless I remove the 5970 from the 16x then it will...

 

[OCGuy]

Can I ask what prompted your purchase decision on this one? Your 5870 is far more powerful than either GPU in that 5970, and Xfire scaling is basically abysmal once you go past 2 GPUS.

Hell, to be fair, scaling past 2 GPUs is abysmal from either company.

 

[apoppin]

Alas all of the above things are present and correct, my commuter won't boot with my 5870 in 4x no matter what I do, unless I remove the 5970 from the 16x then it will...

But it will boot with the cards reversed - 5970 in the 4x slot and the 5870 in the x16 slot right?

Very strange. My last suggestion before i give up and go back to benching is to suggest you update your MB's BIOS (and do a search on your MB's model number and CrossFire-X issues)

Again .. good luck!

 

[HAL9000]

Thanks any way, but it's a Mac pro, no bios...

 

[apoppin]

in that case .. i wish you triple good luck!

 

[HAL9000]

in that case .. i wish you triple good luck!

Haha thanks but I don't feel like I'm losing much, I benchmarked my 5970 at 16x 8x and 4x and I lost 2% at 8x then 5% at 4x and with my overclock being about 17% I dot really think it matters hugely, sure it would be better the other way round but for 5% I'm not going to worry about it, when everything is running smoothly currently.

 

[HAL9000]

Do you think I'd be better off with 8x/8x?