Tech & Gadgets · Head-to-head
Corsair RM850x SHIFT (ATX 3.1) vs be quiet! Pure Power 13 M 850W
Which should you buy? Our verdict on both, pulled from our full The Best PC Power Supplies: 4 Compared (and One to Skip) comparison.
The RM850x SHIFT hits the sweet spot of wattage, Gold efficiency, quiet Zero RPM operation, and a cable layout that makes a modern build look effortless. The Pure Power 13 M matches most of what matters for less, and is the smarter buy if you don't need the SHIFT's tidy side connectors.
Corsair RM850x SHIFT (ATX 3.1)
Buy itThe best-balanced 850W unit for a modern gaming build, with side-mounted modular ports that make cable routing genuinely tidy.
- Cybenetics Gold efficiency with a native 12V-2x6 connector for current PCIe 5.1 graphics cards
- Side-facing modular connectors sit against the motherboard tray, so cables disappear behind it
- 140mm fluid-dynamic-bearing fan with a Zero RPM mode that stays silent under light load
- Fully modular with a 10-year warranty; owners report years of quiet, stable service
- The side-connector layout only pays off in cases designed with the clearance for it
- Priced above conventional 850W Gold units of similar output
be quiet! Pure Power 13 M 850W
Buy itThe value pick: a fully modular, ATX 3.1 Gold unit that runs quietly and undercuts the premium names.
- 80 PLUS Gold with a native 12V-2x6 connector, so it is ready for a current high-draw GPU
- Fully modular cabling at a friendlier price than most premium 850W units
- Temperature-controlled 120mm fan that independent testing and owners describe as very quiet
- Backed by a 10-year warranty, unusual at this price
- Its 120mm fan is smaller than the Corsair units' 140mm fans, though its semi-passive mode does stop it at low load
- Voltage regulation is solid but a step behind the flagship Platinum units under heavy swings
Side by side
The 7 criteria below are the ones our full comparison judged every product on, narrowed to these two.
| Corsair RM850x SHIFT (ATX 3.1) Our pick | be quiet! Pure Power 13 M 850W | |
|---|---|---|
| Our verdict | Buy | Buy |
| Best for | Gaming and creator builds that want ample headroom, quiet operation, and the cleanest cable job. | Mainstream gaming and everyday builds that want modern features without paying flagship money. |
| Price tier | $$$ · premium | $$ · mid-range |
| Wattage & headroom | 850W — ample for one strong GPU | 850W — ample for one strong GPU |
| Efficiency certification | Cybenetics Gold | 80 PLUS Gold |
| ATX 3.1 / native 12V-2x6 | Yes, native 12V-2x6 | Yes, native 12V-2x6 |
| Cabling | Fully modular (side-mounted) | Fully modular |
| Fan behavior | 140mm, Zero RPM mode | 120mm, semi-passive Zero RPM |
| Warranty | 10 years | 10 years |
| Best use | Clean, quiet gaming build | Value gaming build |
Which one is right for you?
Pick the Corsair RM850x SHIFT (ATX 3.1) if
gaming and creator builds that want ample headroom, quiet operation, and the cleanest cable job.
Know before buying: the side-connector layout only pays off in cases designed with the clearance for it.
Pick the be quiet! Pure Power 13 M 850W if
mainstream gaming and everyday builds that want modern features without paying flagship money.
Know before buying: its 120mm fan is smaller than the Corsair units' 140mm fans, though its semi-passive mode does stop it at low load.
The bottom line
Our overall pick is the Corsair RM850x SHIFT (ATX 3.1) - The best-balanced 850W unit for a modern gaming build, with side-mounted modular ports that make cable routing genuinely tidy. Choose the be quiet! Pure Power 13 M 850W instead if mainstream gaming and everyday builds that want modern features without paying flagship money.
Want the full picture, including the other options we compared and the popular one we'd skip? Read the complete The Best PC Power Supplies: 4 Compared (and One to Skip).