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Cooler Master GX 550W review

Our Rating :
Price when reviewed : £65
inc VAT

A long warranty and excellent efficiency let down by the captive design and loud fan

Although it fits into Cooler Master’s budget line of power supplies, the GX 550W is tiny (just 149mm deep), has 80 Plus Bronze Certification and an excellent five-year warranty.

Performance was very good across the board, with no detected problems in our tests. We also measure efficiency at 83.1 per cent at 100 per cent load, 86.32 per cent at 50 per cent load and 85.38 per cent at 20 per cent load. This is at least one per cent more efficient at each load than the supply’s specification.

Cooler Master GX 550W efficiency

This power supply is at least one per cent more efficient than its certification

Unfortunately, it’s not a modular supply, so all of the unused connectors will clutter up your case and make cable management a little bit harder. There are plenty of power connectors for most PCs with three Molex and six SATA for storage. There are two 6+2 pin PCI Express power connectors, which will support any high-end graphics card.

Cooler Master GX 550W

A 120mm fan provides cooling for the PSU, but it was very loud at high loads and potentially quite distracting. In fact, it was one of the noisiest power supplies that we’ve tested.

The GX 550W is certainly a capable PSU, which performed well in our tests and has a long warranty. However, the Be Quiet! Pure Power L8 530W costs around the same, has modular cables, is as efficient and is quieter. It’s the better choice at this price.


Price £65
Rating ***


Size 150x140x86mm
Standard ATX
PFC active
Fans 1x 120mm bottom
Fan control automatic

Claimed Output

3.3V rail 24A
5V rail 24A
Power supply wattage 550W
SLI certified no
CrossFire certified no


Modular no
Molex connectors 3
Floppy disk power connectors 1
SATA power connectors 6
4-pin CPU power connectors 1
8-pin CPU power connectors 1

Buying Information

Price £65
Warranty five years RTB

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