Okay so I have two XFX AMD Radeon R9 270X graphics cards paired with an i5-4670K on an ASUS RoG Maximus VI Hero. The Intel Ark page and my motherboard manual all state that PCI lanes are to be divided up 1_x16 2_x8/x8 3_x8/x4/x4. However my two GPU's instead of sitting at x8/x8 happen to be sitting at x8/x4 and I have no idea why. I do not have any M.2 SSD's or anything else plugged into my PCI slots other than those two graphics cards. In my BIOS I have the top to slots set as Gen 3.0 and the VGA changed from auto detect to PCI. I don't know why it does this and when I remove the second card it goes back to just x8. It doesn't even use the full x16 bandwidth. Is there something wrong with my motherboard/CPU/GPU? I have everything overclocked with the CPU sitting at 4.4 GHz on a water loop and both GPU's are sitting at 1170 MHz core clock (Stock 1050) and 1490 MHz Mem clock (Stock 1400).
I presume you have the cards in the two red PCI-e slots. So this is odd.
In regards to the bios, clear the settings you have put in just to see if there causing any issue.
But anyway your best bet is to re-seat the cards and make sure that the connectors are clear from any gung/dust/whatever.
if you use the first 2 slots, so the x16 and x8 slot. then your Xfire setup will run as 8x.
This does not effect the performance in anyway.
If you only see X8 speeds with just one card installed in slot 1, thats indeed a bit odd. If you monitor with gpu-Z then look if that speeds changes if you go from idle to load
I've been monitoring both GPU's for awhile now and each card in the top slot reads at x8, putting them together either way puts x8/x4 for bandwidth. When idling both cards sit at 300 MHz on the core which is normal. At full speed stock the core hits 1050 and overclocked they hit 1170 with no bandwidth change. Both cards with CrossFire disabled also yield x8/x4 speeds regardless of being paired or individual. I reached out to ASUS to see if it was a motherboard issue, but they said send it in to RMA it. I need my PC and I can't wait wait 3 weeks for them to send a refurbished model back.
Yes but basicly you should rma it realy, because it looks like a faulty mobo to me.
one card in slot one, should simply show 16x speed.