Rank #1 in Best PC Power Supply 2026: 10 Ranked, and the Specs That Don't Add Up
Corsair RM850e (2025) 850W Fully Modular — Black
- Rating
- 4.7
- Ratings
- 310
- Rank
- #1
Price and rating as shown on Amazon when we collected them. Both change.
The CORSAIR RM850e (2025) is the 850W unit that takes first place in this guide, listed at £89.00 and rated 4.7 out of 5 from 310 ratings. It is a fully modular ATX power supply, certified to ATX 3.1 and compliant with PCIe 5.1, with a 12V-2x6 cable, one 120mm rifle bearing fan and 105°C-rated capacitors.
Where several listings in this category contradict themselves, this one holds together. The table gives an Output Wattage of 850 Watts and the name in the title says 850W; the input range of 100 to 240 Volts (AC) covers the roughly 230V of UK mains, which the 90–130V unit elsewhere in the guide does not; and the 120mm fan named in the bullet text is the single fan the spec table lists. It is also the cheaper half of the one genuinely identical pair here: black at £89.00 and white at £94.99, both 15 x 14 x 8.6 centimetres and 1.53 kg. Everything on this page comes from the Amazon listing, not from testing we carried out.
How those 310 ratings break down
An average hides its own shape. This is the spread behind the 4.7 stars.
Specification
Exactly as published on the Amazon listing, field for field.
| Price (as listed) | £89.00 |
|---|---|
| Rating | 4.7 out of 5 from 310 ratings |
| Output Wattage | 850 Watts |
| Input Voltage | 100 to 240 Volts (AC) |
| Cooling | 1 x 120mm rifle bearing fan |
| Dimensions | 15 x 14 x 8.6 centimetres |
| Weight | 1.53 kg |
| Model Number | CP-9020296-UK |
What it is up against
The rivals it was ranked against in Best PC Power Supply 2026: 10 Ranked, and the Specs That Don't Add Up.
Questions people ask
Does the Corsair RM850e suit UK mains voltage?
Yes. The listing gives a Minimum Input Voltage of 100 Volts (AC) and a Maximum Input Voltage of 240 Volts (AC), a range that covers the roughly 230V supplied in the UK.
How much does the Corsair RM850e (2025) cost?
The listing price is £89.00, and it carries a rating of 4.7 out of 5 from 310 ratings.
Is the Corsair RM850e fully modular?
Yes. The listing describes fully modular cabling, so you connect only the cables your system build needs, and the Power Supply Design field reads Full Modular.
What is the fan and how loud is it?
The listing specifies one 120mm rifle bearing fan with a specially calculated fan curve, which Corsair says keeps fan noise down even at full load.
What standards does the Corsair RM850e meet?
It is listed as Intel ATX 3.1 certified and PCIe 5.1 compliant, withstanding 2x transient power excursions from the GPU, and it is compatible with Modern Standby for fast wake-from-sleep times.
What capacitors does the Corsair RM850e use?
The listing states 105°C-rated capacitors, described as delivering steady, reliable power and dependable electrical performance.
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