System Diagnostics

Diagnostics watches your hardware for signs of failure while you use the PC: drive health, memory, GPU trouble, stalled fans and pumps, and sustained overheating. Findings roll up into per-component health verdicts, and Nexus can raise a tray notification that names the specific problem - for example Fan stalled, Pump stalled, Sustained high temperature, NVMe critical warning, or Memory test failed. Open Diagnostics in the sidebar; some checks are platform-specific and show "Not available on this platform" where they do not apply.

1. Summary

The Summary tab shows the overall verdict - Healthy, Needs attention, or Action needed - and a card per component that links into its tab. It also holds Refresh, Export report (a PDF summary), and Export support bundle, which saves one ZIP of logs, diagnostics, and a credential-stripped copy of your settings to attach to a bug report (see Logs & Reporting a Bug). The same bundle is available in Settings under Diagnostics & support.

2. Storage

The Storage tab lists every drive with its bus (NVMe, SATA, USB, RAID), Serial, Capacity, Temperature, Power-on time, and Power cycles, plus a Health percentage "Reported by the drive itself": NVMe drives reflect rated endurance used and remaining spare capacity, SATA drives reflect vendor SMART health attributes. NVMe drives get an NVMe health panel (Critical warning, Available spare, Percentage used, Media errors, Unsafe shutdowns, Data read / Data written, and more); SATA drives get the full SMART attributes table. Each drive carries a status of Good, Caution, Warning, or Bad, with the reasons named (reallocated sectors, pending sectors, high wear level, and so on).

3. Memory

The Memory tab lists your installed modules (Slot, Size, Speed, Manufacturer, Part number) and flags XMP active when an overclocked memory profile appears to be running. Run memory test schedules Windows Memory Diagnostic for the next restart - "The test can take several minutes, during which the PC is unusable" - and the tab shows the last test's result.

4. Cooling

The Cooling tab covers thermals and the GPU:

  • Temperature history - a long-window temperature chart (24h, 3d, 7d, 14d, or pick a specific day; temperature history is kept for 90 days), with a Sustained high temperatures list of episodes in the form "{name} reached {peak} for {duration} on {date}".
  • GPU - Driver version, Temperature, Power, a Throttling readout that names the active limit (Thermal limit, Power limit, Hardware thermal limit, Power brake, or "No throttling active"), and TDR events (30d), the count of GPU driver timeouts.
  • Fans - every fan and pump with a status: OK, Stalled, Suspect, or Unknown, with how long it has been in that state.

5. System

The System tab reads the Windows event logs into an incident timeline: App crash, System crash, Unexpected shutdown, Disk, GPU driver, GPU timeout, Kernel error, Memory test, and Hardware error entries, with counts for the Last 30 days and a shortcut to Open Event Viewer. Below it, Device problems lists devices Windows reports as faulty, with the problem explained in plain language and an Open Device Manager shortcut.

6. Settings

The Settings tab tunes the watchdog:

  • Maximum temperatures - "Nexus flags a component as too hot once its temperature reaches these limits."
  • Warning duration - how long a temperature warning stays visible after the component cools back down (Keep warning for).
  • Notifications - "Show a tray notification when Nexus detects a problem." Enable notifications is the master switch, with per-cause toggles (High temperature, Storage health, Cooling - "Pump or fan stalls.", Memory test failed, Device problems, GPU thermal throttling) and a Notification cooldown between repeat alerts for the same component.
  • Component monitoring - "Turn off a component to stop tracking its health and skip it in alerts."
  • Reset diagnostics settings restores all of the above to defaults.

Tip

Diagnostics answers "is this part failing?"; for live readouts and usage history, use Monitoring instead. If Diagnostics flags a fan, cross-check it on the Cooling page - a fan that stalled because a curve holds it at 0% at idle is behaving, not failing.