asus rog strix z490-e gaming

Hi. Since I have a large heatsink (Noctua NHD14), I can't use the first PCI slot on the motherboard and I have to use the second one. GPUz tells me it's running at x8. The thing is that I thought the secondary slot would go to x8 ONLY if you were using SLI/Crossfire, but if you put a SINGLE gpu...

Hello everyone, I hope someone can help me out here please, Under device manager I have under Other Devices: PCI Device & SM Bus Controller which has the yellow (!) next to them and they won't install properly. The motherboard I have is: ASUS ROG STRIX Z490-E GAMING I'm running on Windows 10...