88C For 5900 is to much it starts to throttle at 85C while 90C is the limit, make sure your cooler is mounted and working correctly.
This is more inline how it should look like:
Manufactures dont provide drivers on CDs or other physical media they simply point you where to download them, you could try this tho https://www.gigabyte.com/Consumer/Software/GIGABYTE-Control-Center/global/
I would start looking in Software problems before swapping all the hardware and noticing no change at all.
Steps to do:
Update BIOS => Check for CPU spikes
Update AMD Chipset drivers => Check for CPU spikes
Uninstall Corsair software => Check for CPU spikes
Reinstall Windows => Check for CPU spikes