Shopping for a mini PC almost always comes down to one nagging question: how much electricity is this little box actually going to use? Manufacturers plaster wattage numbers everywhere — CPU TDP, power adapter ratings, “up to” turbo figures — but almost none of them tell you what the machine draws sitting idle on your desk versus grinding through a video export. That gap leaves buyers guessing, especially anyone running a mini PC around the clock as a home server, NAS, or always-on media box, where idle draw matters far more than peak performance ever will. This guide pulls together every power-related number that mini PC and chip makers actually publish — CPU base and turbo power from Intel and AMD, power adapter ratings from six popular mini PCs, and Apple’s published figures for the Mac mini — and organizes them into a real, side-by-side idle-vs-load comparison. You’ll also learn why a 120-watt power adapter doesn’t mean a mini PC uses 120 watts, how to translate a CPU’s TDP class into a realistic running-cost estimate, and what to watch for so you don’t damage a unit with the wrong charger. By the end, you’ll know exactly which published number to trust, and for which purpose.
| Quick Fact | Number |
|---|---|
| Lowest published CPU base power in this comparison | 6W — Intel N100 |
| Highest published CPU maximum turbo power in this comparison | 115W — Intel Core Ultra 7 155H |
| Smallest bundled power adapter | A small 12V-class adapter — GMKtec NucBox G3 (check the adapter label for the manufacturer’s stated rating) |
| Largest bundled power adapter | 120W — four of the six compared models |
| Apple Mac mini (M2, 2023) power supply | Built-in power supply (AC cord) — 150W maximum continuous power |
| Typical independently-measured idle range, ultra-low-power class | roughly 4W–9W |
| Typical independently-measured load range, H-series class | roughly 65W–110W |
The Short Answer: How Much Power Do Mini PCs Actually Use?
Based on published CPU specifications from Intel ARK and AMD’s product specification pages, mini PC processors span a wide range: a 6-watt Processor Base Power rating for the Intel N100 found in budget fanless boxes, up to a 115-watt Maximum Turbo Power rating for the Intel Core Ultra 7 155H used in higher-end NUC-class machines. Real wall-power draw sits lower and narrower than these chip-level numbers because a full system also includes RAM, storage, a fan or heatsink, and a motherboard that all sip a little power of their own. Across independent testing of similar machines, idle draw for the mini PCs in this comparison generally falls between about 4W and 20W, and sustained full-CPU-load draw falls between about 25W and 110W, depending on CPU class and chassis cooling. Manufacturers themselves rarely publish idle or load wattage directly on their spec sheets — Apple is the notable exception, publishing measured idle and maximum wall-power figures for the Mac mini in a separate support document — but the rest of the industry publishes only CPU TDP and the wattage rating of the included power adapter, which are the two figures we’ll compare in detail below.
Why “Idle vs Load” Matters More Than a Single Wattage Number
A single wattage figure on a box or a product page hides more than it reveals, because almost no mini PC runs at 100% CPU load all day. Two use cases explain why the idle number and the load number both deserve attention, separately:
- Always-on duty (NAS, home server, Pi-hole, media server, smart-home hub): A machine like this might sit at idle or light load for 22–23 hours a day. Even a 5W difference in idle draw compounds into real money and heat over a year of continuous operation.
- Bursty duty (video editing, compiling, gaming, occasional 3D rendering): Here the load number matters more, because the CPU only hits its Maximum Turbo Power for short stretches, and the power adapter needs enough headroom to supply that peak without throttling or shutting down.
Buying based on a single averaged “power consumption” number — the kind sometimes quoted in casual reviews or marketing bullet points — can lead you to overestimate the electric bill of a server-style build, or underestimate the adapter headroom you need for a workstation-style build. Separating idle from load, and grounding both in what’s actually published, avoids both mistakes.
What’s Actually on the Spec Sheet (and What Isn’t)
CPU TDP Is Not Wall Power
Intel and AMD both publish a thermal design power figure for every chip, but they define it differently depending on the generation. Intel now lists two numbers on ARK: “Processor Base Power,” which is roughly what the chip draws running a sustained, non-turbo workload, and “Maximum Turbo Power,” which is the ceiling the chip can hit for short bursts before thermal or power limits pull it back down. AMD lists a default TDP and a configurable TDP (cTDP) range that motherboard and mini PC makers can tune up or down within official limits. None of these numbers include the RAM, SSD, Wi-Fi card, fan, or motherboard VRMs that also draw power — which is why a chip rated for a 28W base power sits inside a system that idles at, say, 10W and peaks well above 28W under full load once turbo kicks in.
Power Adapter Wattage Is a Ceiling, Not a Measurement
The wattage printed on a mini PC’s bundled power brick is an engineering safety margin, not a measurement of typical use. Manufacturers size the adapter to cover the CPU’s Maximum Turbo Power plus everything else in the chassis, plus some headroom for voltage fluctuation and aging capacitors, plus enough spare capacity to charge accessories over USB-C where applicable. A 120W adapter on a chip whose Maximum Turbo Power is rated at 64W is not evidence the machine uses anywhere near 120W in normal use — it’s evidence the manufacturer built in a comfortable buffer.
Full Spec Comparison: Six Mini PCs Across the Power Spectrum
The table below lists the complete published specifications for six mini PCs chosen to span the power spectrum, from a 6W fanless box to a 115W-turbo workstation-class unit and Apple’s very different Mac mini approach.
| Model | CPU & Published Power | Dimensions | Weight | RAM (max) | Storage | Ports | Bundled Power Adapter |
|---|---|---|---|---|---|---|---|
| Intel NUC 13 Pro (NUC13ANHi7) | Core i7-1360P — 28W base / 64W max turbo | 117 x 112 x 54 mm (4.61 x 4.41 x 2.13 in) | 0.6 kg / 1.32 lb (barebone) | 64GB (2x DDR4 SO-DIMM) | 1x M.2 2280 PCIe4 + 1x M.2 2242 PCIe3 | 2x Thunderbolt 4, 4x USB-A 3.2 Gen2, 1x HDMI 2.1, 1x SDXC reader, 2x 2.5GbE LAN, 1x 3.5mm combo jack | 120W (20V/6A; Core i3 kits ship with 90W 19V) |
| ASUS NUC 14 Pro | Core Ultra 7 155H — 28W base / 115W max turbo | 121 x 112.5 x 51.5 mm (4.76 x 4.43 x 2.03 in) | 0.65 kg / 1.43 lb (barebone) | 96GB (2x DDR5 SO-DIMM) | 2x M.2 2280 PCIe4 | 2x Thunderbolt 4, 3x USB-A 3.2 Gen2, 1x USB-A 2.0, 1x HDMI 2.1, 1x SDXC reader, 2x 2.5GbE LAN, 1x 3.5mm combo jack | 120W (check the adapter label for the manufacturer’s stated voltage/current) |
| Beelink SER8 | Ryzen 9 8945HS — 45W default TDP, 35-54W cTDP range | 113 x 113 x 43.5 mm (4.45 x 4.45 x 1.71 in) | 0.75 kg / 1.65 lb | 96GB (2x DDR5 SO-DIMM) | 2x M.2 2280 PCIe4 | 2x USB4 Type-C, 2x USB-A 3.2 Gen2, 2x USB-A 2.0, 1x HDMI 2.0, 1x DisplayPort (via USB4), 1x 2.5GbE + 1x GbE LAN, 1x 3.5mm combo jack | 120W GaN (check the adapter label for the manufacturer’s stated voltage/current) |
| Minisforum UM790 Pro | Ryzen 9 7940HS — 35W default TDP, 35-54W cTDP range | 126 x 126 x 60 mm (4.96 x 4.96 x 2.36 in) | 0.94 kg / 2.07 lb | 96GB (2x DDR5 SO-DIMM) | 2x M.2 2280 PCIe4 + 1x M.2 2280 SATA | 2x USB4 Type-C, 4x USB-A 3.2, 1x HDMI 2.0, 1x DisplayPort 1.4, 2x 2.5GbE LAN, 1x 3.5mm combo jack | 120W (check the adapter label for the manufacturer’s stated voltage/current) |
| GMKtec NucBox G3 | Intel N100 — 6W base power | 106 x 106 x 37.6 mm (4.17 x 4.17 x 1.48 in) | 0.3 kg / 0.66 lb | 16GB (1x DDR4 SO-DIMM) | 1x M.2 2280 SATA/NVMe + eMMC (model-dependent) | 2x USB-A 3.2, 2x USB-A 2.0, 1x HDMI 2.0, 1x GbE LAN, 1x 3.5mm audio jack | Small 12V-class adapter (check the adapter label for the manufacturer’s stated voltage/current) |
| Apple Mac mini (M2, 2023) | Apple M2 — TDP not published | 197 x 197 x 36 mm (7.76 x 7.76 x 1.42 in) | 1.2 kg / 2.65 lb | 24GB (soldered, not upgradeable) | 256GB-2TB SSD (soldered) | 2x Thunderbolt 4, 2x USB-A 3.2 Gen2, 1x HDMI 2.0, 1x Gigabit Ethernet (10GbE configurable), 1x 3.5mm headphone jack | Built-in power supply (AC power cord) — 150W max continuous power |
Source and date: figures above are compiled from each manufacturer’s official spec sheet and, for CPU power figures, Intel ARK and AMD’s specification pages, current as of mid-2024; specs and bundled adapters can change between hardware revisions, so confirm exact figures with the manufacturer before buying.
Typical Idle vs Load Power by CPU Class
Apple publishes measured idle and maximum wall-power figures for the Mac mini directly in a support document, but the other five manufacturers in this comparison don’t publish measured system wattage at all. For those five, the table below translates each CPU’s published TDP class into the range that independent hardware reviewers commonly report for similar machines. These are general guidance ranges tied to CPU class, not manufacturer-measured figures for the specific models above.
| CPU TDP Class | Example Chip | Published Base / Max Turbo Power | Commonly Reported Idle Range | Commonly Reported Load Range |
|---|---|---|---|---|
| Ultra-low power (fanless-friendly) | Intel N100 | 6W / not published as separate turbo figure | 4W–9W | 15W–25W |
| U/P-series efficiency class | Core i7-1360P | 28W / 64W | 8W–15W | 45W–65W |
| Meteor Lake H-series | Core Ultra 7 155H | 28W / 115W | 10W–18W | 60W–100W |
| Ryzen H-series (cTDP) | Ryzen 9 7940HS / 8945HS | 35W–45W default / 54W cTDP ceiling | 10W–20W | 65W–110W |
| Apple Silicon | Apple M2 | not published | 4W–7W (independent measurements of similar Apple Silicon Macs) | 25W–40W |
A Closer Look at Each Power Class
Ultra-Low Power: Intel N100 Boxes Like the GMKtec NucBox G3
With a 6W Processor Base Power and no fan required in many chassis designs, N100-class mini PCs like the NucBox G3 are built for tasks that run all day at low intensity: ad-blocking, file sharing, light home automation, or acting as a thin client. The bundled adapter’s small capacity reflects how little headroom this class needs — there’s no 45W turbo spike to plan for, just a small buffer above the chip’s already-low ceiling.
U/P-Series Efficiency: Intel NUC 13 Pro
The Core i7-1360P splits the difference between efficiency and performance, with a 28W base power that can burst to 64W Maximum Turbo Power for short, demanding tasks. The 120W adapter in the NUC 13 Pro isn’t sized for the CPU alone — Thunderbolt 4 ports can output additional power to connected accessories, and the two 2.5GbE controllers, SDXC reader, and dual SO-DIMM slots all add their own small draws on top of the CPU.
Meteor Lake H-Series: ASUS NUC 14 Pro
The jump to Core Ultra 7 155H brings a much higher Maximum Turbo Power ceiling — 115W versus 64W on the previous generation — even though the base power stays at 28W. This is the clearest illustration of why base power and turbo power need to be read as two separate numbers: at idle or light load, this chip should behave similarly to the older i7-1360P, but under sustained heavy load it can draw significantly more before thermal limits intervene.
Ryzen H-Series: Beelink SER8 and Minisforum UM790 Pro
Both AMD-based machines use a configurable TDP system rather than Intel’s base/turbo split, though their default settings differ: the Minisforum UM790 Pro’s Ryzen 9 7940HS carries a 35W default TDP, while the Beelink SER8’s Ryzen 9 8945HS ships with a 45W default TDP. Both chips share the same AMD-specified 35-54W configurable TDP (cTDP) range, and mini PC makers commonly raise the ceiling toward that 54W limit in firmware to chase extra sustained performance within their cooling budget. Both machines ship with 120W adapters, sized with headroom for that 54W ceiling plus the rest of the system.
Apple Silicon: Mac mini (M2, 2023)
Apple is the outlier in this comparison because it doesn’t publish a TDP figure for the M2 chip at all — Apple’s spec sheets list chip core counts and memory bandwidth, not thermal design power. What Apple does publish, in a separate support document, is measured wall-power draw for the whole Mac mini in “Idle” and “CPU Max” states — an unusual level of transparency compared with the CPU-TDP-plus-adapter-wattage approach the rest of the industry relies on. Apple also publishes the Mac mini’s electrical specs: unlike the x86 machines here, it has no external brick at all — it uses a built-in power supply fed by an AC cord, rated at 100–240V input and 150W maximum continuous power on the M2 model, reflecting the M2’s efficiency-first architecture and the Mac mini’s lack of user-upgradeable, power-hungry expansion slots.
How to Estimate Your Own Mini PC’s Running Cost
Once you know a rough idle or load wattage for your CPU class, converting it into an annual electricity cost is simple arithmetic. The formula is:
- Watts ÷ 1000 = kilowatts
- Kilowatts × hours of use per year = kilowatt-hours (kWh) per year
- kWh per year × your utility’s price per kWh = annual cost
For example, a machine that idles at 10W and runs 24 hours a day, 365 days a year, uses 87.6 kWh annually (10 ÷ 1000 × 24 × 365). At a common U.S. residential rate of roughly $0.16 per kWh, that works out to about $14 per year just to keep it idling. The table below applies the same formula to a few reference wattages from the classes above.
| Continuous Draw | Annual kWh (24/7 use) | Estimated Annual Cost at $0.16/kWh |
|---|---|---|
| 5W | 43.8 kWh | ~$7.01 |
| 10W | 87.6 kWh | ~$14.02 |
| 15W | 131.4 kWh | ~$21.02 |
| 20W | 175.2 kWh | ~$28.03 |
Most mini PCs don’t sit at 100% load around the clock, so a realistic annual estimate usually blends mostly-idle hours with a smaller number of load hours. If you know roughly how many hours a day you’ll push the CPU hard, calculate the idle portion and the load portion separately, then add them together for a more accurate yearly total.
Power Adapter Safety: What the Wattage Rating Actually Protects
The wattage, voltage, and amperage printed on a mini PC’s power adapter aren’t arbitrary — they’re matched to the motherboard’s voltage regulation design. Using a replacement adapter with a lower wattage rating than the original can cause instability, unexpected shutdowns under load, or failure to boot, especially on higher-TDP-class machines where the CPU can briefly demand its full Maximum Turbo Power. Always match the original adapter’s voltage exactly and use a replacement rated at the same wattage or higher, from a reputable brand with proper certification. Never open a power adapter or the mini PC’s internal power circuitry to attempt a repair or modification, and avoid unofficial firmware or BIOS modifications aimed at raising power limits beyond what the manufacturer specifies — both practices bypass safety margins the manufacturer built in for a reason.
Frequently Asked Questions
What’s the real difference between idle power and load power in a mini PC?
Idle power is what the system draws when it’s turned on but not doing meaningful work — sitting at the desktop or running background tasks. Load power is what it draws while the CPU is working hard, such as during video encoding, compiling code, or gaming. The gap between the two can be 5x to 10x depending on the CPU class, which is why a single “power consumption” number is nearly meaningless without knowing which state it describes.
Do mini PC manufacturers publish actual idle and load wattage?
Rarely, on official spec sheets. Apple is the main exception: it publishes measured idle and maximum wall-power figures for the Mac mini in a support document. Most other manufacturers publish only the CPU’s TDP figures (sourced from Intel or AMD) and the wattage rating of the bundled power adapter, not measured wall-power draw for idle or load states — independent hardware review outlets are typically the source for actual measured numbers on those machines.
Is CPU TDP the same thing as the power the whole system uses?
No. CPU TDP (or Processor Base Power / Maximum Turbo Power, in Intel’s current terminology) describes only the processor package. The finished mini PC also draws power through RAM, storage, networking, fans, and voltage regulation circuitry, so total system draw is always somewhat higher than the CPU figure alone, especially at idle.
Why does my mini PC ship with such a large power adapter if it barely uses that much?
The bundled adapter is sized to cover the CPU’s Maximum Turbo Power (or cTDP ceiling), plus every other component in the chassis, plus a safety margin for voltage stability and component aging. It represents a ceiling the system might briefly touch under heavy load, not a typical or average draw.
Which type of mini PC uses the least power at idle?
Based on published CPU base power figures, ultra-low-power chips like the Intel N100 (6W base power) sit at the bottom of the range, and fanless designs built around them, such as the GMKtec NucBox G3, are commonly reported by independent reviewers to idle in the single digits to low teens of watts.
How much does it cost per year to run a mini PC continuously?
Using the formula watts ÷ 1000 × 24 hours × 365 days × your electricity rate, a machine idling at 10W costs roughly $14 per year at a $0.16 per kWh rate, while one idling at 20W costs roughly $28 per year. Actual cost depends on your local utility rate and how much time the machine spends at load versus idle.
Is it safe to use a cheaper, generic power adapter instead of the one included?
Only if it matches the original adapter’s voltage exactly and is rated at the same wattage or higher, from a reputable, properly certified brand. A lower-wattage or mismatched-voltage adapter can cause instability or shutdowns and, in some cases, damage the device. Never open or modify a power adapter yourself.
Does Apple’s M2 chip really use less power than the x86 chips in this comparison?
Apple doesn’t publish a TDP figure for the M2, so a chip-level comparison to Intel’s or AMD’s published base/turbo power isn’t possible. Apple does publish two other numbers worth knowing: measured idle and maximum wall-power draw for the whole Mac mini in a separate support document, and the system’s electrical rating — the Mac mini (M2, 2023) has no external brick, using a built-in power supply rated at 150W maximum continuous power, while most x86 machines here ship with 120W external adapters.
Reviewed and edited by Jason Paik. Spotted an error? Tell us — we verify and correct. See how we create content.