Short answer: in most desktop PCs, Windows cannot tell you the exact make and model of your power supply. The reliable method is to read the label on the PSU itself, check the specification sheet for a prebuilt PC, or look up the original purchase record.
A normal ATX or SFX power supply does not usually report its model, wattage or connector set to Windows. Apps such as HWiNFO, Speccy and CPU-Z can identify many components, but they generally cannot identify a conventional PSU.
How to find out what power supply you have
1. Check the PSU label
This is the most reliable method for a custom desktop.
- Shut the PC down completely.
- Switch the PSU off at the rear if it has a switch.
- Unplug the AC power cable.
- Open the computer’s side panel according to the case manufacturer’s instructions.
- Find the PSU, usually at the top or bottom rear of the case.
- Read the external label for the brand, exact model and rated wattage.
You may need to remove the opposite side panel if the PSU label faces the cable-management side of the case.
Do not open the metal PSU enclosure itself. A PSU can retain dangerous electrical charge even after it has been unplugged. Corsair and Seasonic both explicitly warn users not to open a power supply casing.
Once you have the model number, search the manufacturer’s product page. That is much more useful than simply knowing that the unit is “650W” because you can confirm its connector set, form factor, warranty and specifications.
2. Check your prebuilt PC’s support page
If you own a Dell, HP, Lenovo, Acer or another prebuilt system, start with the exact PC model or service tag before opening anything.
The manufacturer’s specification or parts page may list the installed PSU wattage and sometimes the exact unit. This matters because many prebuilts use proprietary form factors or motherboard connectors, so a normal retail ATX PSU may not be a direct replacement.
3. Check the invoice, order history or build list
If the PC was assembled by a system integrator or retailer, your order confirmation may contain a complete component list. Old emails, retailer accounts and PDF invoices are often the easiest way to identify a PSU without opening the case.
4. Check vendor software only if you have a digital PSU
A small number of premium digital power supplies can report telemetry through manufacturer software. If you already have a compatible digital PSU and its USB/data connection is installed, the vendor app may reveal useful information.
That is the exception, not the rule. If ordinary monitoring software does not show a PSU model, nothing is necessarily wrong.
Can software tell me what PSU I have?
Usually, no.
Most standard desktop PSUs provide power to the motherboard and components but do not expose a standardized device identity to the operating system. That is why Device Manager, Task Manager and most hardware-info utilities can list your CPU, GPU, memory and drives but not your exact power supply.
If a website tells you to download a generic “PSU detector,” be skeptical. Software cannot magically read model information that the power supply never reports.
What information should you read from the PSU label?
The most useful items are:
- Exact model number: the best way to look up the real specifications.
- Rated wattage: for example 550W, 650W, 750W or 850W.
- Form factor: usually ATX or SFX, though the model page is often clearer than the label.
- Input range: the AC voltage and frequency the unit accepts.
- DC output table: maximum output available on the individual voltage rails.
- Efficiency certification: such as 80 PLUS Bronze, Gold, Platinum or Titanium.
- Certification and safety markings.
Wattage is not the only thing that matters
If you are checking your PSU because you want to upgrade a graphics card, do not stop after finding the wattage.
You also need to check:
- whether the PSU has the required GPU power connectors;
- whether it supports the power-transient demands of the new hardware;
- whether the PSU is old enough that replacement makes more sense than reuse;
- whether it physically fits the case;
- and whether the manufacturer recommends enough total system capacity.
Modern high-power graphics cards may use a 12V-2×6 connector rather than only traditional 6-pin or 6+2-pin PCIe connectors. ATX 3.x design guidance also accounts for short power excursions that a simple “GPU watts + CPU watts” calculation can miss.
How much PSU wattage do you need?
PSU & Power Headroom Calculator
Estimate a sensible PSU capacity from your component power figures, desired headroom and the GPU manufacturer’s recommended system PSU. This is a cross-check, not a substitute for the hardware maker’s requirements. Treat the suggested wattage as a capacity target only: connector compatibility, transient loads, PSU age and unit quality can matter just as much as the headline wattage.
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The 650W GPU-maker recommendation is higher than the 592W headroom calculation, so the calculator uses 650W as the minimum target before rounding to a common PSU size.
Important: CPU and GPU specification figures are not guaranteed simultaneous wall-power measurements. PSU sizing also depends on transient loads, connector requirements, PSU age and quality, overclocking, and the manufacturer’s guidance. A PSU rated for more watts does not force the PC to consume that amount.
Avoid the old rule of calculating your estimated draw and simply adding 100W. A better approach is to use the GPU manufacturer’s PSU recommendation alongside a reputable calculator that accounts for your actual CPU, GPU, drives, fans and other hardware. Our PSU headroom guide explains why 20–30% is a useful starting range rather than a universal rule.
The be quiet! PSU calculator, for example, bases its estimate on the selected components and also checks connector availability.
You generally want sensible headroom, but buying a 1200W unit for a system that will never approach that load is not automatically safer or better.
What does 80 PLUS mean?
80 PLUS is an efficiency certification, not a complete quality rating.
The certification program tests how efficiently a PSU converts AC power from the wall into DC power for the PC at specified load levels. Higher tiers include Bronze, Silver, Gold, Platinum and Titanium.
A Gold label does not, by itself, tell you how good the voltage regulation, protections, component quality, acoustics or warranty are. Treat efficiency as one part of the buying decision rather than a substitute for independent PSU quality testing.
What is power factor correction (PFC)?
PFC does not mean the PSU “increases the power” available to your computer.
Power factor correction improves how the PSU draws current from the AC supply. Modern PC power supplies commonly use active PFC. It is a separate concept from conversion efficiency, even though both affect how a PSU interacts with mains power.
Single rail vs multi-rail: should you care?
Do not choose a PSU simply because it has one +12V rail or several. A well-designed single-rail and a well-designed multi-rail unit can both work perfectly in a gaming PC.
What matters more is that the PSU is a reputable design with appropriate protection features and enough correctly rated connectors for your hardware.
Modular vs non-modular PSU
This part of the old advice still holds up:
- Non-modular: every cable is permanently attached.
- Semi-modular: essential cables are fixed, while some peripheral/GPU cables detach.
- Fully modular: all DC cables detach from the PSU.
Modularity mainly improves installation and cable management. It does not automatically mean the PSU is electrically better.
Important: never assume modular PSU cables are interchangeable between models or brands. Use the cables approved for that exact PSU family.
How to check whether your PSU can handle a GPU upgrade
- Identify the exact PSU model.
- Look up its rated wattage and age.
- Check the GPU manufacturer’s recommended system PSU capacity.
- Check which GPU power connector the card requires.
- Confirm the PSU has the correct native cables or manufacturer-approved solution.
- Use a reputable system power calculator as a cross-check.
If the PSU is an unknown-brand unit, very old, damaged, or missing the connectors required by the GPU, replacing it is often wiser than trying to make the numbers barely work.
PSU identification FAQ
Can HWiNFO tell me what PSU I have?
Usually not for a conventional PSU. Some digital PSUs expose telemetry, but most do not report their model to Windows.
Can I find my PSU wattage in Windows?
Not reliably. Windows does not normally know the rated wattage printed on the PSU label.
Can the BIOS show my PSU model?
Usually no. BIOS hardware-monitoring pages may show voltages, but that is not the same as identifying the installed PSU.
Do I need to remove the PSU to read the label?
Often not. Try both case side panels first. In some cases the label is hidden by a PSU shroud or faces the chassis wall, so you may need to partially remove the unit. Follow the case/PSU manufacturer’s instructions if you do.
Is it safe to open the PSU casing to look inside?
No. Open the PC case if needed, but do not open the power supply’s own metal enclosure. Internal capacitors can retain dangerous charge.
Bottom line
For most PCs, the answer is refreshingly low-tech: read the PSU label. If that is not practical, check the prebuilt’s support page or your original invoice.
Once you know the exact model, look up the real specification instead of relying on wattage alone. For an upgrade, connector support, PSU age, build quality and power-transient capability matter just as much as the number printed in watts.
