Best Power Supply Under £100
The power supplies you can buy new for £100 or less, ranked by efficiency rating and cabling. Each price is the cheapest in-stock price we found among the UK shops we check, as of 21 October 2026. Delivery is extra at some shops.
- 1
Corsair RM850e 850W 80+ Platinum Fully Modular ATX 3.1 PCIe 5.1 Power Supply with ThermalProtect - Black
850W, 80+ Platinum, fully modular
£94.99 at Corsair
1 other listing of this model (another size or colour) also at £100 or less.
- 2
Antec HCG850 PRO 850W 80+ Platinum Fully Modular ATX 3.1 PCIe 5.1 Power Supply - Black
850W, 80+ Platinum, fully modular
£99.95 at Overclockers UK; also AWD-IT £133.08
- 3
CWT 1000W PSU 80 PLUS Gold Fully Modular PCIe 5.0 ATX 3.0 Power Supply Unit
1000W, 80+ Gold, fully modular
£96.99 at CCL Computers; also AWD-IT £96.99
- 4
- 5
Channel Well Technology GPX Power Supply, 850W, ATX, 80 PLUS Gold Certified, Fully Modular
850W, 80+ Gold, fully modular
£77.99 at CCL Computers
- 6
MSI MPG A850GS PCIE5 850W PSU 80 PLUS Cybernetics Gold Modular ATX 3.1 PCIe 5.1 Power Supply
850W, 80+ Gold, fully modular
£79.99 at Novatech
- 7
Cooler Master Elite Gold 850W ATX3.1 PCIe 5.1 80+ Gold Fully Modular PSU Power Supply
850W, 80+ Gold, fully modular
£89.99 at AWD-IT
- 8
Gigabyte UD850GM PG5 (rev. 2.0) 850W PSU 80 PLUS Gold Fully Modular PCIe 5.0 ATX 3.0 Power Supply Unit
850W, 80+ Gold, fully modular
£89.99 at CCL Computers; also Overclockers UK £97.99
- 9
MSI MAG A850GL Modular ATX PSU, Black - 850 W
850W, 80+ Gold, fully modular
£89.99 at Currys; also AWD-IT £89.99, MSI £89.99, CCL Computers £107.99
- 10
Seasoinc CORE GX ATX 3.1 850W 80 PLUS Gold Certified Fully Modular ATX Power Supply
850W, 80+ Gold, fully modular
£90.99 at CCL Computers
How we rank
Best 80 PLUS efficiency rating first, then fully modular over semi-modular over fixed cables (a unit listed only as "modular" counts as semi-modular, because the listing does not say which), then more watts, then the cheaper unit. Units without a readable 80 PLUS rating are left out.
Only power supplies with a photo, a full spec table and a new, in-stock price read in the last two weeks are considered, so a part that is sold out everywhere drops off until a shop has it again. Refurbished and used stock is left out. Prices change through the day: check the shop before you buy. We may earn commission when you buy through a link on a product page; it never changes the order here.