Good morning everyone!
Last night I decided to try and consolidate a few mini-rigs that I had and put 4 GPUs on one motherboard instead of having them spaced out between 3 PCs that were set up to mine when idle.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FbN42Lsn.jpg&t=665&c=lcFMQHGYxUWEkw)
Anyways, I built the rig, got the cards raised with PCIe x1 to x16 risers. Everything looked sweet and ready to go, but then when I fired it up the only card that was recognized while on a riser was the one in the PCIE4 slot. I tried the following to no avail:
1) Tried switching the risers out to see if the cards would pick up in the other slots with the confirmed working riser
2) Tried removing the risers, getting the cards to be recognized in Windows 7, then rising them
3) Tried swapping the cards around to ensure that all cards could be recognized in PCIE4 with a riser - they could but no other spot recognizes any card with the risers
After that, I decided to just try and get all 4 of the cards mining to see how it goes, so I put a card in PCIE1, PCIE5, and PCIE6 and used the riser in PCIE4. Success... for about 5 minutes. Had all of the cards hashing away and then after a few minutes GPU3 got sick, then the computer froze and wouldn't restart. I removed GPU3, got the computer back up and running with 3 GPUs, and then GPU2 got sick and the computer froze and restarted. Then I removed that and said "screw it" and I am just confused now.
Details:
System Specs:PSU: Thermaltake Toughpower Grand TPG-1200M 1200W
Mobo: MSI 890FXA-GD70
RAM: 4GB Corsair DDR3
GPUS: 3x5850, 1x6950
Risers: x1 to x16 molex powered risers
My hypothesis is the motherboard is just on it's last leg and that is why the risers only work in one (seemingly random) PCIE slot. The next steps I am going to try before declaring the Mobo worthless for mining is to install Linux and see if that clears anything up. Never worked with Linux before so tomorrow is going to be a fun day
![Cheesy](https://bitcointalk.org/Smileys/default/cheesy.gif)
Any help is much appreciated. Thanks!