The vrm mounting on the front side gave the oddest results. Temperatures rose quickly on the socket to a maximum of 74c, but there was little to no throttling? I have no idea what to say, I could be reading the temps wrong?
The CPU temperatures is coming from a sensor in the socket, or somewhere around the socket, not the actual CPU. The Package sensor is the actual CPU temperature. I had that motherboard before I replaced with with my 990FX Extreme9, and I can tell you that CPU sensor is garbage.
Also, the reason the CPU temperature is getting hotter is because the VRMs are no longer throttling due to heat. When the VRMs were throttling they weren't letting the CPU work as hard, and the CPUs temperature didn't get as high. Putting the fan on the VRM heatsink keeps them cooler, and stops the throttling. You aren't throttling because of the CPU temperate, you are throttling because of VRM temperature, and there isn't a sensor reporting that.
Have a look to see what Realtemp says.
https://www.techpowerup.com/downloads/SysInfo/Real_Temp/
turn off HWMonitor and any other monitoring s/w.
Realtemp doesn't support AMD processors.
Coretemp would work though. However, we are all looking at the wrong temp reading in HWMonitor. We need to be concerned with the Package temp reading, that is the sensor on the actual processor. The "CPU" sensor is somewhere on the motherboard, who knows where and who knows how accurate is actually is. Coretemp will give the same reading as the Package sensor in HWMonitor, because they are reading the same sensor from the CPU.