(The following is for a bitcoin mining set up) Running a RX580 GPU on a ASUS Z97-p mobo. The mobo PCIe setting options are Auto, Gen1, Gen2 yet when my miner is running the PCIe speed kicks up to X16 3.0. I want to run at 1.0 for reasons of power consumption/heat generation. I have set the speed to all 3 settings and no matter what I do, it seems to auto run at 3.0. Showing on GPU-Z as PCIe x16 3.0 @ x16 3.0.
Running the card at pci-e gen 3 would not affect power consumption and heat that much, and most of the change would be because the card lowers it's own speed since it can't kick out enough data, crippling it's performance in a bad way.
Undervolt, and underclock it while keeping the gen 3 speed to reduce heat and power consumption.
lower the power limit in msi afterburner, and then you might be able to oc the ram. faster ram helps. I have a 1650 super mining that is 10mh stock, 12.5 after ocing the ram 900mhz, and lowering power so it never goes above 55c. Toms has a guide somewhere they posted recently.