Can't get CrossFireX to run at x16/x16.

[JMsicarius]

Hello,
My setup is listed below. I know it's capable of running 2 cards at x16, but GPU-z is telling me that i'm running my primary at x16 and my linked card at x8. All other info is identical between the two cards. I've tried fiddling w/ chipset settings in the BIOS, however there's only one setting to change and it doesn't seem to do much that I can tell (something about virtualization, Intel VT-d or something like that). I know neither of my graphics cards would really benefit from the extra 8 lanes, so I'd be happy if i could just get them both running at x8, if that's all i can do. Even if it doesn't matter that they run differently, I'd still like to match them (symmetry issues...). Any help from the crowd is greatly appreciated.

Build (everything is stock clocked)
Motherboard: ASUS Rampage III Formula (Intel X58 chipset)
CPU: Core i7 920 @ 2.67GHz
RAM: 6GB (3x 2GB) Corsair something...
GPU: 2x ATi Radeon HD 5830 (Crossfired)
PSU: Coolmax 1000W (can't remember exact model)
Storage: Intel 80GB SSD (OS and apps), WD 1TB HDD (Media)

Thanks again!

 

[Helltech]

A 5830 will never saturate the x8 lane anyway. You will see no performance difference what so ever at x8 and x16 with that card. Nothing changes with them matching or not.

Do you have your cards in the right slots for x16 x16? To get them both at x16 you must have the first card in the top slot, and the second card in the LAST slot. If you have the second card in the second slot and not third, then that card will run x8, as shown by page 2-29 of your manual.

 

[JMsicarius]

A 5830 will never saturate the x8 lane anyway. You will see no performance difference what so ever at x8 and x16 with that card. Nothing changes with them matching or not.

Do you have your cards in the right slots for x16 x16? To get them both at x16 you must have the first card in the top slot, and the second card in the LAST slot. If you have the second card in the second slot and not third, then that card will run x8, as shown by page 2-29 of your manual.

>.< Now I feel silly. I could swear I read that thing about 50 times, too. If that's what it's going to take, then i'll probably have to forego the option. I tried that when i was initially setting up the rig, but something to do with my case not having enough room prohibited it. Also, I don't think my MoBo came with a crossfire bridge long enough to reach the bottom slot. I may revisit the idea, however, so thank you very much for catching that.

 

[monsta]

You can get the flexible crossfire bridges that are long enough to reach the bottom slot , have a look on ebay, too easy

 

[JMsicarius]

Best answer selected by JMSicarius.