LibreHardwareMonitor: What It Can and Cannot Do

LibreHardwareMonitor is the most widely used open-source hardware sensor library for Windows. It is the foundation under HWiNFO-style monitoring, PRTG custom sensors, Home Assistant hardware integrations, and — under the hood — GGFix itself. It reads temperature sensors, fan speeds, voltages, and clock frequencies directly from hardware monitoring chips, bypassing the Windows abstraction layer that hides most of this data from standard applications. Understanding what it does and does not read matters both for users evaluating it as a standalone tool and for developers building monitoring systems on top of it.

For context on the broader tool landscape, see our PRTG vs HWiNFO vs Open Hardware Monitor comparison and our complete hardware monitoring guide.

What LibreHardwareMonitor Reads

LibreHardwareMonitor accesses hardware monitoring data through several Windows mechanisms:

CPU temperatures: Via Intel MSR (Model-Specific Registers) for Intel CPUs and AMD SMU (System Management Unit) for AMD CPUs. These provide per-core temperatures, package temperature, and TjMax (thermal junction maximum) data. Accuracy is generally within 2–3°C of the actual die temperature on modern processors.

GPU temperatures: Via NVAPI (NVIDIA's official API) for NVIDIA GPUs and ADL (AMD Display Library) for AMD GPUs. For NVIDIA cards, this includes GPU core temperature, VRAM temperature (where available), hotspot temperature (on RTX 30-series and newer), and fan speeds. For AMD cards, GPU core temperature, hotspot/junction temperature, and fan speeds.

Motherboard temperatures: Via super I/O chips (ITE, Nuvoton, Winbond, and others). These provide chipset temperature, PCH temperature, system temperature sensors, and VRM temperature on motherboards that expose VRM thermal data to the super I/O chip.

Fan speeds: Via the same super I/O chips that handle motherboard temperatures. Reads RPM values for all fans connected to motherboard headers (CPU, chassis fans). Does not read fan speeds from fans connected directly to PSU power connectors without PWM headers.

Voltages: +12V, +5V, +3.3V rails, CPU VCore, memory voltage — read from the same super I/O monitoring chips. Accuracy varies significantly by motherboard — some boards report raw ADC values without proper calibration, leading to readings that are systematically off by a fixed offset.

Storage (S.M.A.R.T.): Via Windows StorageWMI interface and direct S.M.A.R.T. command pass-through. Reads drive temperature, wear level, reallocated sectors, power-on hours, and other S.M.A.R.T. attributes for SATA and NVMe drives.

Network interfaces: Basic adapter information.

Battery: Battery wear percentage, charge state, and discharge rate on laptop hardware that reports this data via ACPI.

Known Limitations and Edge Cases

Super I/O chip support gaps: LibreHardwareMonitor maintains a list of supported super I/O chips. Motherboards using chips not in this list (particularly recent or obscure models from smaller manufacturers) may report fewer sensors or no sensors at all. This is the most common reason for "missing" fan speed or voltage data on specific hardware configurations.

BIOS-blocked sensor access: Some motherboard manufacturers block direct hardware register access to prevent third-party sensor reading. This is particularly common on certain gaming-focused motherboards with proprietary EC (embedded controller) implementations. These boards may require manufacturer-specific tools to access fan speed data.

Voltage accuracy: The voltage readings from super I/O chips are sometimes poorly calibrated in the LibreHardwareMonitor database for specific motherboard revisions. A +12V rail reading of 12.3V from a super I/O chip may be the actual rail voltage or a systematic 0.5V offset from an incorrect calibration constant in the library. Cross-checking with a multimeter is the only way to verify accuracy for a specific board.

VRAM temperatures on older NVIDIA cards: VRAM temperature sensors were not accessible via NVAPI on GPUs before the RTX 30 series. For GTX 10-series and RTX 20-series cards, VRAM temperature is not available through LibreHardwareMonitor.

Admin requirements: LibreHardwareMonitor requires administrator privileges to read hardware sensors via MSR and direct hardware registers. Running without admin access results in significantly reduced sensor coverage — typically only sensors accessible via Windows WMI (CPU utilization, disk space) rather than direct hardware reads.

Mobile processors: Intel and AMD laptop processor thermal data is generally well-supported, but the power limit and throttle state information is less consistently available on mobile hardware than on desktop platforms. Not all laptop-specific sensors (keyboard temperature, palm rest temperature on MacBook-style designs) are accessible on Windows laptops.

LibreHardwareMonitor as a Standalone Tool

As a standalone application (open the LibreHardwareMonitor.exe, view the sensor tree), it works well for single-machine hardware inspection:

• Open, run, get sensor data immediately
• View current values plus minimum/maximum observed
• Log to CSV for later analysis (must be manually enabled)
• Can be run as a Windows service (with additional configuration) for persistent operation
• Web server interface (optional) exposes sensor data as JSON for local network access

What it lacks as a standalone tool:

• No automated alerting — the application displays numbers, does not notify you when they exceed thresholds
• No cloud storage of historical data
• No fleet dashboard for multiple machines
• No AI analysis or anomaly detection
• Manual log management required for historical analysis

LibreHardwareMonitor as a Backend Library

The more common use of LibreHardwareMonitor in production monitoring is as a sensor backend library — integrated into a monitoring agent that adds the missing features the standalone tool lacks:

• The GGFix Windows agent uses LibreHardwareMonitor as its hardware abstraction layer, then adds cloud upload, historical storage, AI analysis, and automated alerting on top
• PRTG custom sensors can use LibreHardwareMonitor via PowerShell to pull sensor data into PRTG's monitoring infrastructure
• Home Assistant hardware monitoring integrations often use LibreHardwareMonitor as the Windows sensor source
• Prometheus exporters for Windows hardware use LibreHardwareMonitor as the data source, with Grafana providing the visualization layer

The library is MIT-licensed, actively maintained on GitHub (github.com/LibreHardwareMonitor/LibreHardwareMonitor), and accepts contributions for new hardware support. For developers building monitoring tools, it is the most complete open-source option available for Windows hardware sensor access.

GGFix and LibreHardwareMonitor

GGFix's Windows agent integrates LibreHardwareMonitor as an embedded sensor library. This gives GGFix access to the full range of hardware sensor data that LibreHardwareMonitor supports, with GGFix adding the fleet management, cloud storage, AI analysis, and alerting layers on top.

The practical result: GGFix reads the same sensor data that HWiNFO reads (via the same underlying library access mechanisms), stores it in the cloud, applies pattern analysis across your fleet, and sends alerts when sensors deviate from established baselines. The sensor reading layer is proven and broadly compatible; the monitoring intelligence layer is where GGFix adds value beyond what any standalone sensor reader provides.

Frequently Asked Questions

Is LibreHardwareMonitor safe to install?

Yes. LibreHardwareMonitor is an open-source project with a published codebase on GitHub. It requires administrator access to read hardware registers, which is standard for hardware monitoring software. The project has been in development since 2020 (forked from the original Open Hardware Monitor) and is widely used in the hardware monitoring community.

Why does LibreHardwareMonitor show different temperatures than HWiNFO on the same machine?

HWiNFO reads a broader set of sensors and applies more hardware-specific calibration than LibreHardwareMonitor in some cases. For CPU temperature, the readings should be within 1–2°C. For motherboard/ambient sensors, differences of 3–5°C are possible due to different calibration constants for specific super I/O chips. For critical temperature decisions, HWiNFO is generally considered the higher-accuracy reference tool.

How does LibreHardwareMonitor handle new hardware?

LibreHardwareMonitor updates its hardware database with each release. New CPU microarchitectures (Intel Arrow Lake, AMD Zen 5), new GPU generations, and new motherboard super I/O chips are added in subsequent releases. Newly released hardware may have partial sensor coverage until a library update adds full support. If you see missing sensors on new hardware, check if a newer LibreHardwareMonitor release addresses your specific hardware.

Can LibreHardwareMonitor run as a Windows service without a user interface?

Yes, with configuration. LibreHardwareMonitor can be wrapped in a Windows service using NSSM (Non-Sucking Service Manager) or similar service wrapper tools. The web server interface (which must be enabled manually) allows querying sensor data via HTTP without a visible UI. This is the typical configuration for using LibreHardwareMonitor as a monitoring backend.

Does GGFix use LibreHardwareMonitor?

Yes. GGFix's Windows agent embeds LibreHardwareMonitor as the hardware sensor abstraction library. This gives GGFix access to the same hardware sensor data that dedicated diagnostic tools read — CPU temperatures, GPU temperatures, fan speeds, voltages, S.M.A.R.T. data — with the GGFix layer adding cloud telemetry, AI analysis, and automated alerting on top of the raw sensor readings.