Some brands of motherboards defaults the PCIe slots to Gen2 & we must manually select Gen3 for optimal performance.
Also, cooling is a major issue here, at least with your MB. One could fry eggs at that temp (or boil water). You need to perform a serious cleaning & if needed, add fans (a basic system needs one intake & one exhaust). I run two intakes & one exhaust of the Noctua brand on my main PC & have them all running at 100% all the time with a Noctua device for the job. It detects the RPM via a single PWM port (4 pin fan header) & makes sure all runs it's max (or set) speed. For those with 3 pin fans, there's a knob on the device to make these run wide open or however desired.
At any rate, I have a hunch the temp of the MB has something to do with this. I recommend as
julienruc was saying in downloading Adwcleaner (it's free!) & run a scan as Administrator. It'll find common infections & fast, plus any bloatware, you may skip these if desired. The serious infections will be lit in red, any pre-installed software will be orange. I run it once weekly for prevention on all of my computers, also reboot the modem & router by unplugging each & allow to stand for a minute, if nothing else, will speed the connection if not done in a long time.
You motherboard needs airflow in a bad way, especially around the VRM's. These are the various heatsinks, used to be more copper, these days more aluminum. It's possible with some models to replace the thermal paste on these heatsinks, however please check on your MB model as to how.
This could be why
everything is running slower than normal, other than the GPU, according to your UserBenchmark report.
Good Luck!
Cat