Why doesn't Windows boot after CPU upgrade?

I recently bought a i5 9600K for my gf's computer from the internet (not from a computer shop). I wanted to check if it's working so I put it into my computer, which usually runs a 9400F. It boots up into bios, but I also wanted to check if it boots into windows, which apparently it does not. Why?


So, is it only about installing a fresh copy of Windows? The PSU that I've chosen has the proper power rating for the 9600k, and the SSD that I'll be installing will be new (i.e. it will have a fresh Windows installation on it).

4 Answers

  • 4 weeks ago

    David's answer is right. Just because both are 9th Generation processors, doesn't mean the 9600k is compatible with your system. Your system might be limited to non-K processors like the i5-9600 or i7-9700. OEM systems from HP, Dell, Acer, and Lenovo sometimes have very limited CPU compatibility. 

    Are you even sure the system is passing the Power On Self Test and are you able to get into the BIOS with the 9600k?

    Despite the 9400f and 9600k being cut from the same cloth/wafer, a BIOS update or resetting the BIOS might help. It might also help to try booting up with 1 stick of RAM, try each stick. The 9600k might have a bad memory controller. Also, it would be a good idea to remove the CPU and inspect the socket field.

    Yes, sometimes the current O.S. doesn't play well with a new CPU and reinstalling Windows has been been known to get the system past the hump. I've upgraded or swapped CPU's on quite a few systems, and I've never had trouble with the O.S. but I've heard of a few people that have. The Product key is tied to the motherboard and not the CPU or any other random component. I've gotten a few used motherboards, Installed Win10 to a blank SSD, and the product key was automatically activated after everything was all said and done. Even if the product key is not active or invalidated, Windows 10 will continue to boot but with a watermark in the corner of the screen. 

    It would be a good idea for you to research the system or motherboard to see what CPU's are known to be compatible. Like I said, OEM systems have limited CPU compatibility. If a Core i7-9700 is compatible and the 9600k isn't then the system has done you a favor. I could see upgrading to an i7-9700, i7-9700f or i9-9900 but going from one i5 to another won't do much to help with processing power or gaming.

    The CPU cooler not being installed correctly with new thermal compound can also cause an issue of this sort. 

  • keerok
    Lv 7
    4 weeks ago

    Newer win versions are so restrictive that they register the processor and motherboard detail during installation. If you replace one of them or both, you will be required to purchase a new license to run windows again.

    There are workarounds. Keep searching.

  • David
    Lv 7
    4 weeks ago

    You will need to post the details of the motherboards of you and your girlfriends computers. Just because the CPUs have the same pinout doesn't automatically guarantee compatibility. The BIOS, memory and chipset have to be compatible, did you check on the manufacturers website?

    Windows shouldn't complain about the slightly different processor, It certainly shouldn't trigger an activation/validation request as the other are suggesting - even then you would be able to boot into windows.

    Initially clear the CMOS and reset the BIOS to defaults, after that if no better see if there is a BIOS update.

    If you post more details of the motherboard I can check compatibility on the makers website

    The other possibility is that you bought a faulty CPU from the internet

  • 4 weeks ago

    Because you installed a new CPU and on your hard drive are drivers that match your old CPU it's called the chipset Windows is trying to find the old CPU. But it's not there. You can try to enter the recovery console and once you're in the recovery console I turning your computer off and on off and on and off and on until the recovery console starts try to do a reset this PC. And save your files. if this does not work you're going to have to totally reinstall Windowswhat you should have done before you installed the new CPU ways to go into the device manager and delete the chipset drivers under CPU processors and then shut your computer down then you install the new CPU then you go into BIOS and you push the word defaults then you save and you exit and you attempt to start your computer your computer should find a new CPU driver as soon as it starts up

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