Unable to enable crossfire

[banj0chicken]

Hello all, I am having a bit of trouble enabling crossfire on my 2 XFX Radeon HD7870 Ghz Edition graphics cards. The option for crossfire just does not show up in the CCC.

http://i.imgur.com/U9hQnhk.png
http://i.imgur.com/AHU9iAY.png
http://i.imgur.com/54MGp9x.png

As you can see my computer detects the 2 cards just fine.

I have the crossfire bridge installed my motherboard is an Asus P8Z77-V which has 3 PCI-E slots
and I have one card in the blue slot and the other in the white slot.

Link to motherboard: http://www.asus.com/Motherboards/P8Z77V/

I could just be missing something obvious as this is my first time installing duel graphics cards.

My motherboard box says that it supports ATI CrossFire and SLI Bridge so I just don't get why the option is not showing to enable crossfire.

Do I need to edit some BIOS settings to get it working?

Appreciate any support on this issue.

Thank You.

 

[Damn_Rookie]

Sorry it worked out this way, but I'm glad I could at least help explain your issue.

I agree entirely; they should of made it clearer with the naming of the Tahiti LE cards. AMD takes some of the blame, but it was made even more complicated by the fact that different manufactures used different terminology to identify the cards that were Tahiti LE based rather than Pitcairn based, and failed to explain the significance of this.

Sadly, the chart you linked doesn't have the Tahiti LE based 7870s listed, as they really are a different beast entirely and should be listed separately between the 7870 and 7950. Really, Tahiti LE based 7870s should be grouped with the 7900 cards, as you can crossfire them with the 7900 series cards (as they're both based on the Tahiti chip), but not the 7800 series.

 

[Pinhedd]

Wait a second, your GPU-Z images may have solved this. One is listed as a Pitcairn GPU, and the other is a Tahiti GPU. This would suggest that one of your 7870 cards is a 7870 XT, and is based on a cut down Tahiti chip, called the Tahiti LE (Tahiti was the chip used in the 7950 and 7970), as opposed to the Pitcairn GPU that powered the normal 7870 and 7850. The differing numbers of shaders between the two cards confirms it.

There were some very confusing naming schemes when the Tahiti LE based cards were released, such as calling them 7870 XT, or 7870 PCS+ Myst edition - really they should of just called it the 7930, or something similar. Sadly this naming situation has led you to your current predicament, as unfortunately you cannot crossfire those two cards as they have different GPUs powering them.

Excellent catch