LED on CPU turns red following some time spent installing Windows – problems arise after upgrading components.
LED on CPU turns red following some time spent installing Windows – problems arise after upgrading components.
Hello everyone, I chose to enhance a few parts of my computer and carry out a fresh Windows install. However, in short, I’m seeing a red CPU indicator after just a short while of setting up Windows. The upgrades I made are: SSD: Crucial M500 → Samsung 980 Pro PSU: CoolerMaster GX750W Bronze → Seasonic Prime TX-850 CPU: Ryzen 5 3600 → Ryzen 9 5950X The unchanged items are: Mobo: MSI B450 Tomahawk MAX GPU: AMD RX480 8GB CPU Cooler: Arctic Freezer Esports 34 Duo RAM: G.SKILL Flare X Series DDR4 3200 MHz CL14 I prepared by: 1) updating BIOS to the latest version 2) using household alcohol to remove old thermal paste 3) purchasing Arctic MX6 thermal paste 4) making a Windows bootable USB drive After the installation, I tried to start but was quickly redirected to the BIOS with a warning about CPU temperature. That was a mistake—I forgot to connect the cooler (long workday, sorry). I reconnected it and restarted. Once the setup finished, I selected a keyboard layout during Windows install. The system briefly shut down, then resumed. It still worked: my USB boot detected and the installation began. But after choosing a layout, the PC went silent—mouse, keyboard, screen off, fans spinning, and the CPU LED illuminated. I tried again several times, but the same outcome occurred: a minute of installation followed by that persistent red light. A few observations: I didn’t alter BIOS settings since removing the old CPU, PSU, and SSD. The Ryzen 9 5950X appears in BIOS with all 16 cores detected. XMP remains disabled, RAM runs at 2400 MHz. If I enable XMP, RAM jumps to 3200 MHz but the issue persists. The temperature climbed slowly—around 43°C in a 20°C room after roughly two minutes of monitoring in BIOS. I used the same cooler as before and removed old paste correctly. Anyone have suggestions on what to check first? Thanks!
Found this on the 550 board—it might be related. I encountered a similar problem on that board with a Ryzen 9 5950X and fixed it. Here’s what I did: I unplugged the unit, removed the RAM (Kingston Fury Renegade 16 GB x2 if needed), turned off all fans, etc., and used a screwdriver to connect the JBAT1 pins (the battery was still attached). Then I created a thumb drive partition with just 1 GB, formatted it as FAT32, and installed one of the two BIOS updates from MSI (unzipped and renamed to MSI.ROM). After flashing the BIOS via the nifty port and button, the CPU light came back. But when I reinserted the RAM, the DIMM light appeared again. I tried the second BIOS update listed on MSI’s site, but the CPU light stayed on with the RAM in and the UDIMM light when the sticks were removed. I placed just one stick in (channel A2), secured it firmly (it’s tricky on this board), and the system worked—video appeared through the EVGA GeForce RTX 3060, which can’t output via its shield ports without a capable CPU. Once everything loaded to UEFI, I added the second stick (in UDIMM B2) and a drive (M.2), and loaded Win11. Now I notice the CPU light flashes on at power-on for a moment before turning off. It takes a few seconds after pressing the PWR button to boot. Probably a BIOS issue. The board was supposed to support Ryzen 5 and AM4 right out of the box, but it didn’t. I also saw some discussions about the LED staying lit after a BIOS update or CPU change.
I took a significant leap from the 2019 version to the 2022 one without making gradual changes because I wasn’t sure it was required. To decide which updates to apply when doing incremental updates, you should check the manufacturer’s website for guidance. Based on what I found online, you only need to update incrementally if they explicitly state so.
I verified the power cables from the PSU are correctly connected to the motherboard (the PSU is new). I removed the cooler and cleared the thermal paste. I unsocketed the CPU and used compressed air to ensure it was clean. I inspected the CPU pins for any damage and found none. I reapplied thermal paste, reinstalled the cooler, and powered up the system. Result: The same issue occurred; I could perform a few mouse movements to proceed with the Windows install, but the CPU shut down repeatedly displaying a red light on the motherboard.
I reviewed the MSI site to revert to an earlier BIOS build. I updated the BIOS from version 7C02v3F dated 2022-08-12 to 7C02v3C dated 2022-01-18. The installation finished smoothly, and the system has been running steadily for roughly two hours without any issues. Thread marked resolved.
I'm still stuck and need to start over. I attempted to install the drivers for the wireless adapter using a USB stick, but everything stopped again with the CPU light on the motherboard. After rebooting, Windows prompted for a password just like before. Ugh.
A user reported needing to enable PBO in the BIOS to stop the CPU LED when using a 5900X on an MSI B450 Tomahawk MAX. This adjustment appears effective based on their experience.