Upgraded CPU, now GPU not recognized

Thomas Panza · December 27, 2019

(Solved now, but just want to share how I solved it) The problem: I had just upgraded my CyberpowerPC CPU from an I5 6402P to an I7 7700, and then my existing GPU (RX 480 4Gb) was no longer recognized.

How it manifested: After I installed the new CPU and restarted the PC, my screen was black, but I could hear the Hard drives working. I had to plug the monitor to my MOBO for it to work. Then I checked the Device manager, display adaptors, and the only adapter showing was the CPU's Integrated graphics adapter (Intel 630).

I tried every suggestion I could google, nothing worked, including:

-Putting the previous CPU back, ( I used the fan that came with the new CPU though as it was easier to install, instead of the old fan that required screws, you'll see why this is relevant later). Didn't work

-Disabling the MOBO display adapter and removing the GPU, then reinstalling the GPU, hoping that the hardware(the GPU) was recognized. Didn't work.

-Taking some of the RAM out, in case there was some conflict with memory allocation. Didn't work.

-Reinstalling the Operating System ( I was desperate). Didn't work.

-Checking the pins in the CPU socket in the motherboard,to see if some of them were bent. I thought two of them looked bent, So I used a needle to try and align the pins. (not sure if it worked, at some point I thought I had completely messed up the CPU socket, they're too small)

Finally, I got lucky:

After trying all of the above solutions unsuccessfully I decided I needed to put my old CPU back, and return the new CPU. But that meant I had to install the old Fan, as the new Fan came in the box with the CPU. Inadvertently, this solved the mystery.

The cause of the problem was the new CPU fan: I used the Intel push pin kind that came in the box with the new CPU, which does not put enough pressure on the CPU against the CPU MOBO socket. Only after I replaced the push-pin fan with the screw/spring type fan that I had with my previous I5 CPU ( a screw/spring type fan), the GPU was recognized and showed up in the Display adapter list under Device manager. ( trying to align the CPU socket pins may had been part of the solution, but I would suggest not to mess with them, until after you check the fan first).

Hope this helps other people with the same problem.