PSU Compatibility Checker
Check your power supply can run your build: total wattage, headroom, GPU connectors including 12V-2x6, and the 80+ efficiency rating.
Will your power supply run this build?
Wattage is only half the question. A 1000 W unit is useless if it lacks the connector your graphics card needs, and a nominally adequate unit can still shut the system down if it has no headroom for transient spikes.
Connectors decide whether it works at all
Modern high-end cards use the 12V-2x6 connector (previously 12VHPWR). Cards that ship with an adapter can run from three or four 8-pin PCIe cables, but a native connector is cleaner and safer. Critically, each 8-pin cable should feed one connector — daisy-chaining two connectors from one cable, which many PSUs allow physically, runs the cable well beyond its comfortable rating on a power-hungry card.
Headroom protects against transients
Graphics cards draw power in extremely short bursts that can exceed their rated figure by 50% or more for a fraction of a millisecond. A power supply running near its limit may trip its over-current protection during one of these spikes, which appears as a sudden reboot with no error message. Aim to sit around half the unit's rated capacity in normal use.
Efficiency, briefly
80 PLUS ratings describe how much wall power reaches your components: roughly 85% at Bronze, 90% at Gold, 92% at Platinum. The practical benefits are lower heat and quieter fans rather than a meaningful saving on the bill — you can check that yourself with the Electricity Cost calculator.
Age matters more than people think
Capacitors degrade. A power supply that comfortably ran a system five years ago may no longer deliver its rated output, and reusing an old unit with a new high-end graphics card is a common cause of mysterious instability. Most manufacturers rate consumer units for around five to seven years of regular use.
If you are choosing a new unit rather than checking an existing one, start with the PSU Calculator.
Frequently asked questions
Can I use PCIe adapters for a 12VHPWR card?
The adapter supplied with the card is designed for it and is safe when fully seated. Third-party adapters and daisy-chained cables are where problems arise. A power supply with a native 12V-2x6 cable is the cleanest solution.
Is it safe to daisy-chain PCIe power cables?
On a card drawing under about 200W, generally yes. On anything more, use a separate cable per connector. A single 8-pin PCIe cable is rated for 150W, and daisy-chaining asks one cable to carry double that.
How much headroom should a PSU have?
Aim for typical load around 50-60% of the rated wattage. That leaves room for GPU transients, keeps the unit in its most efficient band, and usually means the fan stays off or slow.
My PC restarts under load - is it the PSU?
It is the most common cause. Sudden reboots with no error, specifically under gaming or stress load, point to over-current protection tripping on transient spikes, or to an ageing unit that no longer delivers its rating.
Can I reuse my old power supply?
If it is under about five years old, from a reputable maker, and has both the wattage and the connectors, yes. Beyond that, capacity fades - and a failing PSU can take other components with it.