Hi. I'm on win 10, 64 bit, using SGMiner 5.5.5.
Currently I have 2 GPUs: Sapphire RX 470 Nitro+ and Gigabyte RX 570 Aorus.
I'm experiencing the strangest thing: when one of the cards is connected to PCIe x16 slot (number 1) - be it using riser or directly - it provides bigger and more stable hashrate.

Example:
- RX 470 is in PCIe x16 slot (via riser) - gives ~900 H/s stable, no slowdowns after 20+ hours;
- RX 570 is in PCIe x1 slot (via riser, the one just above PCIe x16), - gives ~860 H/s on average, but with slowly degrading performance. It could go to 840 or even less gradually.

Now I know one might think "you have different overclock settings, BIOSes, the GPUs are different after all", BUT! When I switch PCIe connections of these cards - RX 570 starts to mine w 900 H/s stable, and RX 470 drops as described.
So could PCIe x16 be the difference here? I don't see how though, since both of the cards are connected via PCIe x1 risers. Thanks.

EDIT: there's one more thing - none of the included OC settings are working, for example "gpu-vddc" doesn't set (I set it in global part of the config). I believe it's to do with the drivers, right? I use latest crimson blockchain for W10.
However, there's another issue - SGMiner resets core voltage of all GPUs every so often. This happens with MSI Afterburner closed and/or open. I don't face such an issue with any of claymore's miners. Anyone has a solution for this? Thx.