My Windows 11 PC boots normally, but every day it eventually becomes almost unusable. The mouse starts lagging, windows take a long time to close, and even HWiNFO once took about 10 minutes to open. Task Manager shows low usage during the slowdown—CPU around 7–13%, memory around 45%, and disk activity around 1–3%. The CPU stays near 50°C, so it does not appear to be thermal throttling. It feels like the system is waiting on something rather than being overloaded.
The slowdown can begin anywhere from about 20 minutes to an hour after booting. Windows Reset also hangs indefinitely; one attempt ran for more than 24 hours without completing.
The system has a Ryzen 7 5700X, ASUS PRIME B550M-K motherboard, 16 GB of DDR4-3200 memory, an MSI RTX 3060, and a Kingston NV2 500 GB NVMe drive with roughly 247 GB free. The BIOS has been updated from its original 2021 version.
So far, I have checked the SSD with CrystalDiskInfo, which reports 97% health, 3% used, 100% spare, no media errors, and a full PCIe 4.0 x4 connection. Memory tests passed, DISM and SFC completed without finding system corruption, and I reseated the RAM, graphics card, and M.2 drive. I also completely disassembled and rebuilt the PC except for the CPU and cooler. The monitor works normally with another computer.
There was also a separate issue where the monitor briefly lost signal. Replacing the HDMI cable stopped the flickering and the PC worked normally for several days, but the severe slowdowns eventually returned. I have also disconnected the external backup hard drive, and the problem still occurs. Ubuntu showed the same behavior, so it may not be limited to Windows.
Could the HDMI cable improvement have been coincidental? Given the clean software and storage tests, should I focus next on the power supply, motherboard, GPU, or another component?
3 Answers
Since the same issue appears under Ubuntu, Windows and its drivers are much less likely to be the root cause. Try booting a live Linux environment with the NVMe drive removed so the test bypasses both the installed operating system and primary storage. If the lag still happens, concentrate on the GPU, motherboard, PSU, RAM, and connected peripherals.
If the live environment is stable but Windows is not, create a bootable Windows installer and perform a clean installation rather than relying on Reset. A Reset can hang when the existing installation or storage path is already damaged. Back up important files first, and disconnect any secondary drives during installation.
The fact that it happens every day but anywhere from 20 minutes to an hour after boot suggests that timing and background activity may be useful clues. Check Event Viewer, Reliability Monitor, scheduled tasks, and background utilities while the system is still responsive. A process can be waiting on hardware or drivers without showing high CPU, memory, or disk usage.
To isolate the hardware, test with all optional USB devices and external drives disconnected, and try a different keyboard, mouse, and display if possible. The HDMI cable may have been a coincidence, although a loose or failing GPU port could explain the signal drops. The cable alone should not normally make the entire operating system unusable.
It happens every day, just at different times. I disconnected the external hard drive, and I’ll try different peripherals and another GPU if I can borrow one.
At this point I would treat the motherboard, graphics card, and power supply as the main suspects. A failing PSU or motherboard can cause stalls and device timeouts without producing obvious temperature or utilization spikes, though a GPU or its port could also explain the earlier display dropouts.
There is no reliable software test that completely clears a PSU or motherboard. If possible, test with a known-good PSU and a different GPU, one at a time. Also inspect Windows Event Viewer for display-driver resets, WHEA hardware errors, storage timeouts, or USB/controller errors.
I agree that the motherboard or GPU seems more likely than a simple Windows issue. The temporary improvement after changing the HDMI cable makes the GPU output or port worth testing, even though it would not normally explain every symptom by itself.
I have already seen the problem while using Ubuntu, so I’ll try testing with the NVMe removed as well. If the hardware tests point back to Windows or the drive, I’ll use a USB installer for a clean installation instead of Reset.