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
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 buyers actually say
Quoted from customer reviews on Amazon
Verified purchase“Really happy with the CORSAIR RM850e (2025). I'm using it in my gaming PC alongside an NVIDIA GTX 1080 and MSI MAG Z790 TOMAHAWK MAX WIFI motherboard, and everything works together perfectly.The 850W capacity gives me plenty of power for my setup, and I've experienced zero stability or power-related issues. It simply gets on with doing its job, which is exactly what I want from a power supply.Being fully modular is a big advantage when building a PC. You only need to connect the cables your system actually requires, which makes cable management considerably easier and helps avoid having unnecessary cables stuffed inside the case.I've also been very happy with the noise levels. It's not something I find distracting during normal use or gaming, and the overall build quality feels exactly like what I'd expect from a good Corsair PSU.It pairs very nicely with my Z790 motherboard and GTX 1080 setup, and installation was straightforward.A PSU isn't necessarily the most exciting component in a PC, but it's one of the components you really don't want causing problems. So far this has been reliable, quiet and completely trouble-free.Excellent build quality, fully modular, quiet and works perfectly with my setup. Very happy with it. ⭐⭐⭐⭐⭐”
Verified purchase“Fantastic piece of kit - runs silently, more than enough different cables to install everything I needed for a full gaming rig. Compatible with a majority of old and new components, and with it being modular, only use the cables you need, avoiding filling up the case with unnecessary cabling and restricting airflow.”
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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