MisterJ has an excellent suggestion if you are having problems with Windows after upgrading your CPU.
But changing or updating your CPU really doesn't involve any new Windows drivers to be installed. The only change, in my opinion, will be performance under Windows unless, for some reason, the CPU is not compatible with the Windows installed. Then you would need to upgrade your Windows. But when you upgrade your CPU then you probably may need to reconfigure your Motherboard's BIOS or upgrade your motherboard's BIOS to make it work with the new CPU.
If you are upgrading Motherboards then it is recommended to make a clean install of Windows. Different Motherboards have different CHIPSET Drivers for their hardware or chips. So, in my opinion, it is a good idea to start with a fresh Windows installation without any of the old motherboard's drivers installed that may cause conflicts with the new motherboard.
When I had Windows 7, I upgraded my CPU from a AMD Phenom II x4 to a FX 8350 x8 CPU. Never reinstalled Windows 7. After installing the new FX CPU had no issues at all. Windows 7 worked better with the new CPU performance wise.
From Microsoft Technet about reinstalling Windows after CPU change but was having BSODs and other Windows problems: Do I need to re-install windows after CPU swap?
Thank you for detailed information (Intel Ark is the best source of Intel CPU).
When I asked you to provide information, I guessed there were differences of TDP and generation.
But, as far as our information goes, I cannot find any significant difference between two CPUs.
You don't have to reinstall Windows 10 after replacing CPU.
I guess some hardware-related faults are in your PC. CPU fan, thermal grease, power supply, etc.
Please check all parts especially from points of thermal, power, connection.
(It's rare, but probable, that pins/connectors on CPU are broken.)
Best regards,
Ashidacchi
Tuesday, August 15, 2017 1:31 PM
Restart your computer and see if all 4 cores are now active.