Quick answer: AMD has confirmed a Radeon driver bug where the External Events Utility (atieclxx.exe) can keep writing to the system drive even at idle. A fix is planned for Adrenalin 26.11.1, expected later in November with no exact date.
If you run a Radeon graphics card, your system drive might be getting written to nonstop, even when the PC is sitting idle. AMD has confirmed the bug, and the fix is planned for Adrenalin 26.11.1.
The process behind it is the AMD External Events Client Module (atieclxx.exe), part of the AMD External Events Utility that handles things like monitor detection and Radeon software hotkeys. Users have reported constant writes of 0.3 MB/s to 1.5 MB/s, and one Reddit user saw about 5 MB/s. At 5 MB/s that works out to around 432GB a day, but VideoCardz and Tom's Hardware both point out that these are theoretical numbers and the real effect on SSD wear hasn't been established. TechPowerUp ties the reports to Adrenalin 26.10.1 and 26.10.2, and VideoCardz notes that not every Radeon system is affected.
AMD acknowledged the reports in October. According to VideoCardz, an AMD representative later said the problem looks like an interaction between the External Events Utility and Microsoft's PCIe filter driver, and that Adrenalin 26.11.1 should fix it. That driver is expected later in November, but AMD hasn't given an exact date.
To check your own PC, press Win + R, type resmon, open the Disk tab and sort by writes. Look for constant writes from atieclxx.exe. Until the fix lands, users have reported two workarounds: disabling AMD External Events Utility in Windows Services, or turning off Resizable BAR in the BIOS. Neither works in every case. Disabling the service can break Adrenalin hotkeys and some display functions, and turning off Resizable BAR can cost gaming performance.