@joykiller check that your connectors in motherboard pcie sockets do not touch each other.
You mean the x1 connectors? Those are not touching, the USB wires are, but its been like this now for over a year and had no issues.
Yes, make sure the usb female connector of each x1 adapter is well spaced from the back contacts of the adjacent x1 connector board. It is a known issue for motherboards where each pcie socket is too close to the other one, like in the Asrock H110 Pro BTC+. I stopped having random gpus falling off the bus as soon as I covered each connector with isolating tape.
You mean wrap the USB Cable in aluminium foil tape? Or you talking about the x1 Slot wouldnt that cause issues with conductivity on the board? Got a picture for reference please?
I've seem'ed to get it working so far, its been going for over 24h so far as it has in the past year, but if the foil tape helps increase hashrate due to frequency noise maybe might be worth it. I got some tape laying around.
No. What LukePicci was meaning is that in boards where the pcie connectors are close to each other, the side of the x1 connector, might touch the flat part of usb female connector of next x1 connector. This might disable the slot at best, or create short circuits.
in order to prevent this you should place isolating tape on the side of the x1 connector. You should cover with tape the parts highlited in red in the picture.
If you exclude too aggressive overclocking, 90% of the instability problems on a rig are coming from poor power distribution. Two pieces of advice:
1) the pcie cable to SATA provided with the risers is generally of crappy quality. In any case the SATA connector cannot take more than 50-55W, so you should connect the pcie riser to a 6pin PCI cable directly to the power supply or through a pcie splitter.
2) If you have a dual power supply configuration, you should power the motherboard and all PCI risers with the same power supply. You will use the second power supply to power the top connectors of the GPUs only. This will prevent ground loops and many headaches.