Not sure how much it consumes during gaming but it's a thirsty CPU at the best of times. From memory I have at least one other PCIe slot on the PSU I can try and I think two.When you mention it improved using 2 saperate cables it makes me think PSU , how much power does Threadripper 1920x even use during gaming ?
Do you have anymore PCIe slots on PSU just to try instead? Or does it only have 2 ?
I am inclined now to get a new PSU, 1000W, as it'll just be bringing the purchase forward a bit. I guess a little extra in postage as I'll get the rest of the build separately later. But it'll give me more confidence in the cause. And if it is the CPU I'll send AMD a big apology for blaming their drivers.