RTX 50 user builds better ROG Astral power warning tool, shuts PC down when connector current gets too high
A GeForce RTX 5090 owner has released a free monitoring tool designed to add another layer of protection for ASUS ROG Astral graphics cards. Called 12VHPWR Guard, the application monitors current across all six 12V power pins and can automatically shut down the PC if one pin remains above a configured limit.
The software was developed ROG Astral GeForce RTX 5090 user. ASUS already provides per-pin current monitoring through GPU Tweak III, but userwanted the system to take action automatically instead of relying on the user seeing a warning. His tool checks all six pins twice per second and triggers a shutdown if any pin remains above 9.5A for 15 seconds. ASUS uses a 9.2A threshold for its own warning.
So I built a small watchdog. It sits in the tray, polls all 6 pins twice a second, and if any pin stays above 9.5A for 15 seconds straight it force shuts down the PC. The threshold and timing are configurable but the defaults are conservative on purpose, transient spikes and normal load swings won’t trigger it. For reference ASUS’s own warning threshold is 9.2A.
© CoolerThanNos ROG Astral sensors become an active protection system
12VHPWR Guard reads the ITE IT8915FN monitoring chip installed on supported ROG Astral cards directly through NVIDIA’s NVAPI and the GPU’s I2C bus. HWiNFO shared memory is also supported as a fallback. The developer says access is read-only and that the readings were compared against HWiNFO under loads approaching 500W, with differences of no more than 0.02A per pin.
The application currently supports the ROG Astral RTX 5080 OC, RTX 5090 OC, RTX 5090D OC, RTX 5090 LC and RTX 5090 Matrix. These models expose individual current readings for all six power pins. The program runs on Windows 10 and Windows 11 and requires Python 3.10 or newer. Users can also change the current and duration thresholds from the tray application.
12vhpwer-guard Features
- Monitors GPU 12VHPWR Pin1-Pin6 Current
- Standalone: reads the card’s own sensor chip directly, no HWiNFO required
- Falls back to HWiNFO SM2 shared memory if the direct path is unavailable
- Requires sustained threshold breach (default: 15 s)
- Force-closes blocking apps during shutdown so nothing can stall it (on by default; SHUTDOWN_FORCE_CLOSE_APPS in the source)
- Silent background operation
- Tray icon UI with live status
- Configurable settings via tray menu (threshold amps, sustained seconds)
- Persistent configuration saved to config.ini
- Pause / Resume from tray
- Toast notifications
- Windows Event Viewer logging
- Quiet rotating file logs
- Detects sensor loss (HWiNFO exit/crash/freeze, or I2C failure) and auto-reconnects; never reports OK on stale data
- Resets its timer across sleep/resume instead of trusting a stale reading
- Single-instance guard (a second copy exits instead of double-monitoring)
- Uses Task Scheduler as watchdog
The tool does not prevent every possible 12V-2×6 connector failure, and the developer describes it as an additional safety measure rather than a replacement for proper cable installation. Still, it makes direct use of hardware monitoring already available on ROG Astral cards and adds an automatic response that ASUS GPU Tweak III currently does not provide. By default, 12VHPWR Guard forces a shutdown after a pin exceeds 9.5A continuously for 15 seconds.
Source: Reddit , 12vhpwer-guard (Github)
