I'm having major issues with my 750GH/s Monarch. When i plug my 500GH/s versions into my PSU, they work fine. But when i plug my 750GH/s model in, nothing happens. I have to turn the PSUoff and on again to get it working with my 500GH/s model. Please help!
I have a couple that are doing weird things as well, I will try underclocking based on Kuschelweich's post and report back.