It depends on how many watts your PC averages, how many hours it runs and what you pay per kWh, and 77Fox measures what the CPU and GPU draw. On Windows it logs CPU and GPU power and temperature from their sensors, keeps up to 365 days of history, and turns the energy used in any period into a cost once you enter your electricity price. Hardware monitoring is free and runs only in the Windows desktop app, after a one-time administrator approval.
What 77Fox tracks
77Fox detects Intel and AMD CPUs and NVIDIA, AMD and Intel graphics, integrated or discrete. With more than one GPU, you choose which cards to show. Graphics readings come from the GPU vendor's driver first. Long model names are shortened, so "AMD Ryzen 9 9950X3D 16-Core Processor" becomes "R9 9950X3D".
| What | Details |
|---|---|
| Live readings | Hover the 77Fox tray icon for a card listing each CPU and GPU with its temperature and power. The dashboard widget and the device cards on the hardware monitor page show them too. Sampled every 2 seconds by default, or every 1, 3, 5 or 10 seconds if you prefer |
| History ranges | 1h, 6h, 24h, 7d and 30d, plus 60, 90, 180 and 365 days under More |
| Metrics | Temperature (min, avg, max), power (average watts) and energy (Wh, switching to kWh past 1,000 Wh), for the CPU and each GPU separately, with totals at the top |
| Retention | Per-minute data for 30 days; hourly summaries for 366 days |
| Storage | On this PC only; never synced |
By default 77Fox records temperature and power for the CPU and discrete GPUs. Under Settings → Hardware monitor → History you can tick temperature, power or load for each device; anything unticked still shows live but isn't stored. The Tray section of the same page decides which devices appear in the tray card.
Set your price and see the monthly cost
- Open the hardware monitor page and scroll to Energy usage.
- Right-click the Cost figure (or focus it and press Enter) to open "Set electricity price".
- Type your price per kWh, pick a currency and press Enter. Clear the box and save to remove the price.
- Choose a range next to the Energy usage heading, such as 30d, or 365 days under More. The left figure is the energy used in that range and the right one is the cost. Without a price, the cost shows "—".
77Fox uses a single price per kWh. If your tariff has peak and off-peak rates or tiers, enter your own estimate of the average rate, and the cost follows that figure.
History builds up from the day you start. After a few days, take the 7-day cost, multiply by 30 and divide by 7 for a rough monthly figure; once a month or a year is recorded, pick 30d or 365 days directly.
To get a feel for the numbers, here are two hypothetical machines at two assumed prices. Neither price is a real tariff; they're examples:
| Scenario (hypothetical) | Average power | Hours a day | kWh a day | kWh in 30 days | At $0.17/kWh | At £0.25/kWh |
|---|---|---|---|---|---|---|
| Coding, some rendering | 180 W | 8 | 1.44 | 43.2 | $7.34 | £10.80 |
| Local model left running | 300 W | 24 | 7.2 | 216 | $36.72 | £54.00 |
The first row works out as 180 W × 8 hours = 1,440 Wh, or 1.44 kWh a day. Over 30 days that's 43.2 kWh, which comes to $7.34 at $0.17 or £10.80 at £0.25. The second row: 300 W × 24 hours = 7.2 kWh a day, 216 kWh in 30 days, $36.72 or £54.00.
Real use is rarely a flat line. 77Fox adds up the measured power between each pair of samples, so the peaks of a long inference run and a quiet idle afternoon both count as they happened. A 30-day or 365-day total therefore follows how you actually use the machine more closely than a single wattage times hours.
Why a wall meter reads higher
77Fox counts what the CPU and GPU sensors measure, plus any peripheral estimates you add. Power supply conversion losses and the motherboard aren't included, so the figure comes in below what the machine draws from the wall. To see the whole PC's draw, compare it with a plug-in power meter.
| Part | How it's counted |
|---|---|
| CPU | Measured by its sensor |
| GPU | Measured, vendor driver first; integrated graphics power is already inside the CPU reading, so it isn't added twice by default |
| Display | Estimated once you add it, from size, resolution, refresh rate and brightness |
| Memory, SSDs, hard drives, fans | Estimated once you add them, as count × typical watts each |
| Motherboard, PSU conversion losses | Not counted |
| Sleep, shutdown, or 77Fox not running | Not counted, and not filled in later |
You add peripherals under Estimated peripherals on the hardware monitor page: Display, Memory, SSD, Hard drive, Fan or Custom. Memory and drives come pre-filled with the count 77Fox detected, and Custom takes a wattage directly. Estimates stay visibly separate from measurements: a three-color bar under Energy usage splits CPU, GPU and estimated peripherals, and the history chart draws the estimate as a gray dashed line you can switch off. Estimates aren't written to the history database; they're applied only to the minutes that actually have samples.
Reading the temperatures
Temperatures on the live device cards change color, and the CPU and GPU each have their own thresholds. The same 75°C is still yellow for a CPU but already orange for a GPU.
| Device | Green: normal | Yellow: warm | Orange: hot | Red: critical |
|---|---|---|---|---|
| CPU | Below 65°C | From 65°C | From 80°C | From 90°C |
| GPU | Below 55°C | From 55°C | From 70°C | From 83°C |
Drives and other devices with a temperature sensor can be added to the history: tick temperature for them under Settings → Hardware monitor → History, and they get their own line on the temperature chart.
A jump into orange during a render, a build or a model run usually just means the chip is busy. The history tells you more: switch to 7d or 30d, and if the average sits in the hot band for days, check the cooling, from dust and stalled fans to blocked airflow. After cleaning or changing a cooler, compare the average temperature of two 7-day stretches under similar load to see whether it helped. Safe limits differ by model, so go by the manufacturer's figures.
When a sensor can't be read, 77Fox shows "—", and the curve breaks at the gap instead of dropping to 0°C.
First run: one administrator approval
Reading low-level CPU sensors needs administrator rights, so 77Fox asks once:
- In the Windows app, open the hardware monitor page and click "Authorize hardware monitoring".
- Windows shows a UAC prompt; choose Yes. 77Fox registers an on-demand task with elevated rights, and you won't see the prompt again.
- 77Fox itself keeps running with normal user rights; only that sensor task has administrator rights.
If you choose No, the page says low-level CPU sensors are unavailable, and you can authorize later. To undo it, remove the elevated task in Settings → Hardware monitor.
Hardware monitoring shares the monitor page with server latency and VPS traffic. To put the readings on your dashboard, see An all-in-one dashboard toolbox for vibecoders, or download 77Fox for Windows to start.
FAQ
Does it work on laptops?
Yes. Integrated graphics are detected, and on laptops with a discrete GPU both are listed separately. Integrated graphics power is already part of the CPU reading, so it isn't added to total power and energy by default; the "Include iGPU power in total power" switch in settings counts it, at the risk of counting it twice.
Is any of this uploaded?
No. Temperature, power and energy history stay on this PC. They aren't part of Google Drive sync, and you don't need to sign in to see them.
Does time asleep count?
No. Energy only builds up while the PC is on, 77Fox is running and samples are coming in. A gap of more than 30 seconds between samples, from sleep, shutdown or quitting 77Fox, isn't filled in. Peripheral estimates follow the same sampled minutes.
What if a reading shows "—"?
77Fox shows "—" or a driver hint instead of a zero or a guess. If the page says the CPU driver isn't active yet, open Settings → Hardware monitor and click "Re-detect and repair CPU monitoring"; if that doesn't help, restart Windows. Before enabling that officially signed driver, 77Fox checks its version, hash and digital signature. GPU monitoring doesn't depend on this step, and GPU readings come from the vendor's driver first.
Can I see it in the web version?
No. Hardware monitoring runs only in the Windows desktop app; the web console and the Android app don't read local hardware.