While we see all the beautiful UI during Windows 10 installation, know that drivers are important and need free storage disk to complete installation, your processor is equally important. If you are getting the CompareExchange128 error during Windows 10 installation, the CPU lacks an important instruction called as CMPXCHG16B. This results in the CompareExchange128 error during Windows 10 installation. As a matter of fact, CMPXCHG16b, PrefetchW, and LAHF/SAHF is a criterion for using Windows 10 64-bit version when upgrading from an earlier version of Windows.
What is CMPXCHG16B instruction
The CMPXCHG16B instruction performs an atomic compare-and-exchange on 16-byte values. This instruction may also be referred to as CompareExchange128. Atomic compare-and-exchange means that CPU compares the contents of a memory location with a given value. If they are the same, modifies the contents of that memory location to a new given value. I know its technical, but it gives you a bit of idea.
CompareExchange128 error during Windows 10 installation
This happens only with the 64-bit version of Windows 10, and the only way to resolve it is getting an update on hardware level from the OEM, but if nothing works, its time you get a new CPU.
1] Update BIOS and Chipset Drivers
It’s best if you can figure out if your OEM has an update for your PC BIOS and related chipset drivers. You should first check the BIOS version. In the Search bar, type msinfo32 into the search and press Enter. Once the System Information Tool opens, you can check the BIOS version.
Next, you need to use the BIOS utility that came with your Laptop or PC, and then use it to upgrade. This is different for every PC. In case you don’t have it, look up at the OEM website, and see if there is an option to download.
2] Downgrade to the 32-Bit version of Windows 10:
If BIOS update is not available, you may switch to the 32-bit version of Windows instead. This will bring restriction on the amount of installed RAM, and other places, but if that’s not a problem, you can switch. Many use 64-bit for better hardware features, RAM, and other things.
3] Buy new hardware
If your PC is way too old, it’s better to buy a new hardware or a completely new PC which can keep up for next couple of years. I had to replace my 10-year-old Dell Laptop even though it was able to upgrade to Windows 10 but wasn’t able to keep up. Make sure to check all the features, and compatibility with Windows 10.
See this post if you Can’t install Windows, Processor doesn’t support CompareExchange128.