Different hashrate, Crossfire or pci slot?

Hi, (I’m French, sorry if my english is bad)

I have got two rigs with two Asus RX580 4GO for each one.
1st rig : Gigabyte H170-HD3, GPU0 on PCI16-1 and GPU1 on PCI16-2 with risers
I’m forced to plug my video card on pci16 because otherwise the rig doesn’t start (i don’t know why)

2nd rig : Gibabyte GA-G61M-DS2, GPU0 on PCI16 and GPU1 on PCI1-1

I use the same BIOS for my cards, the same miner version, the same risers, the same driver, the same Windows version.
The only difference is the motherboards : that of my first rig allows Crossfire and that of my second rig don’t

I mine Ethereum and i’ve got 29mh/s on each cards, except on my first rig :

With Claymore dual mining i’ve got 29mhps on my GPU0 and 18mhps on my GPU1

Then I don’t know why when I tried to reverse the slot and then reset to the original position, according to windows, the GPU2 becomes the GPU1
Then with Claymore dual mining i’ve got 16mhps on my GPU0 and 29mhps on my GPU1

With GPUZ the memory controller loading of the GPU which mine at 16mhps is only at 60%, that could explain the difference of hashrate.

To resume : When I tried to reverse the slot and then reset to the original configuration, the GPU0 primary become secondary and the GPU1 secondary become primary (for Windows and for the drivers). So, their hashrate haved reversed, and this difference can be cause only by a Crossfire (I think)

BUT, I can’t disable the Crossfire in AMD radeon settings. I can’t find the option (look at the screeshoot)

Driver version : Win10-64Bit-Crimson-ReLive-Beta-Blockchain-Workloads-Aug23 here

Do you know why the rig doesn’t start when I plug the videocards to pci16 and pci1 ?
Do you know why I’ve got this difference of hashrate ?
Do you know how to disable a Crossfire ?

Thank you ! :slight_smile: