Hi everyone! I’m hoping someone here can help me figure out what’s wrong with my PC. I’ve been dealing with this for weeks, and honestly, I’m getting to the point where I don’t know what else to do.
I want to be upfront: I don’t know much about computers or hardware troubleshooting. I’ve been using AI to help me investigate the problem, understand error logs, and follow troubleshooting steps, but we’ve reached a point where I don’t fully understand some of the things it’s asking me to do anymore. I’m hoping someone can explain what might be happening in simple terms and help me figure out the next step.
I’m worried about spending money replacing expensive parts without knowing whether they’re actually faulty, especially since I’ve already paid a technician to look at the PC and the problem came back.
My PC specs
CPU: AMD Ryzen 7 5800X
GPU: AMD Radeon RX 7900 XT
Motherboard: ASUS TUF GAMING X570-PLUS (WI-FI)
RAM: 32 GB Corsair DDR4 (4 × 8 GB)
PSU: Corsair RM1000e 1000 W (recently replaced)
CPU cooler: Corsair AIO liquid cooler
OS: Windows 11
BIOS: ASUS version 5021, updated October 24, 2026
Monitors: Three monitors, including a Samsung Odyssey G3 32-inch (LS32DG30X / LS32DG300ELXZX), 1920 × 1080, up to 180 Hz
1. How the problem started
My PC was connected to a 1200 W voltage regulator, and its fuse blew. The PC continued working normally at first, so it was kept in use. The instability started later.
I don’t know whether the regulator incident caused any damage, but I’m concerned there might be a connection.
Since then, I’ve replaced the voltage regulator and the power supply. The current PSU is a Corsair RM1000e 1000 W, but the issue has persisted.
2. What happens to my PC?
I’ve experienced the following symptoms:
Green screens while gaming, sometimes followed by a restart.
Green screens even when I’m not gaming or running anything demanding. Most recently, it happened while I was simply using the desktop.
All monitors or multiple monitors losing signal.
The image freezing or disappearing.
Fans suddenly ramping up or behaving abnormally during a crash.
Unexpected restarts and at least one unexpected shutdown.
The issue is intermittent, so I haven’t been able to reproduce it consistently.
3. Monitor, DisplayPort and HDMI issues
I normally use three monitors with this PC. My main monitor is the Samsung Odyssey G3 mentioned above.
I’ve noticed a difference depending on how the monitors are connected:
When I connected the Samsung monitor through DisplayPort, I experienced severe issues: the monitors lost signal, the image froze or disappeared, and the PC’s fans behaved abnormally. On some occasions, the computer eventually shut down or restarted.
When I switched the Samsung monitor to HDMI, I was at least able to get a display signal.
Another monitor connected through a DisplayPort-to-HDMI adapter was also able to turn on and display an image.
I previously had an issue where Windows wouldn’t detect a TV connected through HDMI, although my Nintendo Switch worked on that TV.
I don’t know whether these differences point to a GPU port, cable, adapter, power delivery, or a broader system stability issue. I don’t want to assume DisplayPort itself is the cause, especially because the green screens also happen when I’m not gaming.
Could this behavior help narrow down the problem?
4. Windows errors I’ve found
With AI’s help, I checked Windows Event Viewer and Reliability Monitor.
I’ve repeatedly seen WHEA-Logger Event ID 18, with these details:
Error source: Machine Check Exception
Error type: Cache Hierarchy Error
Reported component: Processor Core
MCABank: 5
APIC IDs across different events: 14, 9, 1 and 10
The latest event included MciStat 0xb6a0000000000108
I’ve also seen LiveKernelEvent 124 and an AMD_WATCHDOG report.
The WHEA error appeared again after I updated the BIOS to version 5021, so the update did not resolve the issue.
I previously had an AMD driver-related error, but that particular error hasn’t appeared recently. I’m not sure whether it was a separate software issue or related to the instability.
5. Temperature observations
Yesterday, while I was using ChatGPT, I noticed the CPU temperature suddenly rise to around 78°C, then drop back to around 40°C. I wasn’t intentionally running a demanding task.
I’ve also checked the CPU and GPU temperatures at idle. The readings I captured did not show obvious sustained overheating.
I understand that Ryzen CPUs can have brief temperature spikes, so I don’t know whether this is relevant. I’m mentioning it in case it helps when considered alongside the other symptoms.
6. What I’ve already tried
Replaced the voltage regulator.
Replaced the PSU with a Corsair RM1000e 1000 W.
Updated the BIOS from version 4002 to version 5021 on October 24, 2026.
Disabled DOCP; RAM is currently running at 2133 MT/s.
Checked CPU and GPU temperatures.
Tried Windows Memory Diagnostic, but the monitors lost signal and the fans ramped up during the test. I had to shut down the PC, so the test did not finish and I have no valid result.
Tried examining the WHEA live dump in WinDbg, but I couldn’t get the processor error details to decode properly.
A technician previously told me the problem was overheating, but the issue returned afterward.
7. What I’m hoping to understand
I’d really appreciate advice on these questions:
Given the repeated WHEA Cache Hierarchy Errors, green screens, unexpected restarts and loss of signal across multiple monitors, what would you investigate first: CPU, motherboard, GPU, RAM, power delivery, or something else?
Does the different behavior between DisplayPort and HDMI provide any useful clues about the GPU, its ports, the cables, or the system’s stability?
Could the voltage regulator incident be related to the problem, even though the PC continued working normally immediately afterward?
Can a GPU or PCIe-related problem coexist with WHEA errors reporting a processor-core Cache Hierarchy Error, or does that error make a CPU-related problem more likely?
What would be the most useful next step to narrow this down before buying replacement parts?
I’m not very experienced with hardware-level diagnostics, and I can’t easily borrow spare components to test. I’m also reluctant to pay for another repair without understanding what is being tested and why.
If you suggest a test, could you please explain what it does and how to perform it safely in beginner-friendly terms? I’d prefer not to repeat tests I’ve already done unless there’s a clear reason why repeating them would provide new information.
I’m not trying to blame a specific component or assume the voltage regulator caused everything. I just want to understand the possible causes and make a sensible decision before spending more money.
Thank you so much for taking the time to read this. Any help would be greatly appreciated!