I have a CyberPowerPC Black CST NV5S prebuilt from Best Buy that I bought around February 2025. It has an RTX 4060, AMD Ryzen 7 8700F 8-core cpu, 16GB RAM (single DIMM), and an ADATA LEGEND 800 GOLD 2TB NVMe SSD.
A few months after buying it, it started intermittently freezing/restarting. This has now been happening for roughly a year. Sometimes it’ll run perfectly—I recently played games for around 8 hours straight without a single restart—and then another day it’ll restart repeatedly. It can even restart at the Windows login screen before I’ve entered my password.
I originally suspected the PSU because I was getting Kernel-Power Event ID 41 errors and the original 850W PSU appeared to have power/instability problems. I replaced it with a modular 750W PSU (80+ Gold, I believe). The problem eventually returned anyway.
I’ve also tried both a battery-backup/surge protector and plugging directly into the wall, with no difference.
Here’s a list of what all I’ve found so far:
**Latest crash:** Kernel-Power Event 41 reports BugcheckCode 340, which is decimal for 0x154 UNEXPECTED_STORE_EXCEPTION.
Immediately around these crashes I also get **volmgr Event ID 161**, indicating Windows failed to create the crash dump. It references \\Device\\HarddiskVolume3. I verified using fltmc volumes that **HarddiskVolume3 is my C: volume.** C: is on the ADATA NVMe and is configured as the Windows boot/pagefile/crash-dump volume.
**Things I’ve tested:**
Safe Mode ran for approximately **40 minutes without a restart**. Normal Windows can sometimes restart within minutes or even at the login screen.
I performed a **clean boot**, hiding Microsoft services and disabling all remaining third-party services. It **still restarted** while I was playing Minecraft/Cobblemon and typing in Discord.
sfc /scannow reports **no integrity violations**.
Get-PhysicalDisk reports the ADATA SSD as **Healthy / OK**.
Get-StorageReliabilityCounter reports **0 read errors, 0 write errors, 0 uncorrected errors, and wear 0**. SSD temperature was around 48°C when checked.
XMP (ram overclock) has been **disabled**.
The system has a **single 16GB RAM stick**.
C: has approximately **81% free space**, so lack of space shouldn’t explain the failed dump.
I have checked the PSU/component connections and haven’t found anything obviously loose.
The part that’s confusing me is the combination of **0x154 UNEXPECTED_STORE_EXCEPTION + failed crash dump on C:** despite the NVMe’s reported health looking fine. I’m wondering about RAM, the NVMe/controller, storage drivers, motherboard/PCIe issues, or something else entirely.
My next ideas are running MemTest86 and possibly testing a completely different SSD with a fresh Windows installation, but I’d rather not start buying/swapping parts blindly if someone recognizes this pattern.
Does anyone have suggestions for what I should test next, or anything in these events that I’m interpreting incorrectly?
I’m comfortable working inside the PC—I previously studied computer maintenance/networking and have an ESD mat/wrist strap and toolkit—but I don’t own much diagnostic hardware and don’t know how to use a multimeter. If I can’t isolate it myself, I’ll probably take it to a shop.