This may sound like a silly question, but do you have the cards setup to use SLI or Crossfire?
You could think this is strange and maybe it is, but I have an R9 390 and a 1080Ti Fe. I had the amd first but because of upgrade reasons I bought the new 1080Ti.
I start mining when Zcash had low dif and then I was willing for a upgrade, that's why I ended with two brands of cards before you ask.
this is indeed weird, I haven't encounter nor read this type of problem before, have you tried installing and checking on GPU-Z, basically it does display your GPU's, what I am thinking is to use atiwinflash app for checking device info, this is for checking only and don't do flashing. if you have validated that it is indeed using a single device number, then I guess you have a faulty mb.
Sorry for delayed answer I passed through some trouble and had to put mining aside.
Check those pictures. This is the location windows map cards.
https://i.imgur.com/ZooSjMX.pnghttps://i.imgur.com/MdF427z.pngAnd this is my gpu-z screenshots.
https://i.imgur.com/oN7Tudn.gifhttps://i.imgur.com/US1BtzE.gifWhich GPU is in the 16x slot? If it's the R9 I would run DDU to remove all drivers, shutdown and then remove the 1080. Then power on and install the AMD drivers first. Then shutdown and install the 1080 again and install the nvidia drivers.
R9 is on X16 slot. I guess a windows reinstall would be the answer. Going to to it if nothing changes.
Your description is confusing, maybe a language issue. It seems you said the miner can distinguish between the
two cards, if so is there really a problem? If everything works properly maybe it's normal. I've never installed two cards
from different manufacturers so I'm just speculating.
Not a language issue. It is really confusing.
It seems you said the miner can distinguish between the two cards, if so is there really a problem?
It keeps using the same rail for both cards, this is what I'm trying to mean when it should use 1 rail for each card, x1 slot take x16 rail performance down when using both cards, so much that is even more profitable use one card only if mining.