Best Overall Value
Price: £84.23 | Rating: ★★★★½ (4.7)
The RM750e (2025) is basically the RM650e with an extra 100W of headroom, and it comes in at the same price point. So why isn't it number one? Honestly, for most mid-range builds the extra wattage is unnecessary. But if you're running a more demanding GPU or you just like having breathing room, this is the smarter long-term buy.
The spec sheet is identical to the RM650e in almost every way. Cybenetics Gold efficiency. Fully modular. ATX 3.1 compliant. Native 12V-2x6 connector for PCIe 5.1 cards. 105-degree-rated capacitors. Modern Standby Mode. The difference is purely in the wattage ceiling, and for anyone pairing this with an RTX 4070 Super, RX 7800 XT, or planning a future GPU upgrade, that extra 100W is genuinely useful.
Build quality feels solid. The cables are well-sleeved and the connectors click in properly without feeling flimsy. Fan noise is impressively low under moderate loads, which is what you'd expect from the RM line. It only really spins up under sustained full-load gaming sessions, and even then it's not intrusive.
At £84.23, this represents excellent value for a Gold-rated fully modular PSU. The fact it's ATX 3.1 compliant means it's properly ready for current-generation hardware, not just technically compatible. For anyone serious about building a system that'll last, this is a strong contender for the best Corsair power supply under £100 in the UK right now.
Pros
- 750W gives proper headroom for demanding GPUs
- Gold efficiency and fully modular at a competitive price
- ATX 3.1 and PCIe 5.1 compliant
- Very quiet under typical gaming loads
- 105-degree capacitors for long-term reliability
Cons
- Overkill for lighter or office builds
- Marginally more expensive than the RM650e
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Best Build Quality
Price: £88.69 | Rating: ★★★★½ (4.6)
Right. This one is a bit of a surprise. The CX750 comes in at under £45, and for that you get 750W of 80 Plus Bronze-rated power. That's a lot of wattage for the money. If your budget is genuinely tight and you need a reliable PSU that won't let you down, this is the one to look at.
It's non-modular, so all the cables are permanently attached. That's the main compromise. In a smaller case, cable management can get messy. But in a mid-tower with decent space behind the motherboard tray, it's manageable. The sheathed cables are a nice touch at this price point, at least making things look a bit tidier than bare wires.
80 Plus Bronze means around 85% efficiency at 50% load. Not as good as Gold, but perfectly acceptable for a budget build. The fan is reasonably quiet under normal gaming loads, though it's not in the same league as the RM series for noise levels.
For a first build, a budget gaming rig, or a secondary PC, the CX750 is genuinely hard to fault at this price. You're getting 750W from a reputable brand with a decent warranty. The lack of modularity and the Bronze rating are real compromises, but they're compromises you're knowingly making in exchange for saving a significant chunk of money. That's a fair trade for many builders.
Pros
- 750W for under £45 is exceptional value
- 80 Plus Bronze certified for decent efficiency
- Sheathed cables help with tidiness
- Corsair brand reliability and warranty
Cons
- Non-modular design makes cable management harder
- No PCIe 5.1 or ATX 3.1 support
- Fan can be audible under heavier loads
Buy on Amazon£88.69
Best for Beginners
Price: £54.98 | Rating: ★★★★½ (4.6)
The newer CX650 (ASIN B0CJRXX5WT) is a solid entry point for anyone building their first PC. It's straightforward, reliable, and priced accessibly. 650W covers most mid-range gaming builds comfortably, and the 80 Plus Bronze certification means it's not wasting electricity unnecessarily.
Being non-modular is the obvious limitation. Every cable is permanently attached, so you'll need to tuck away the ones you don't use. For beginners, this actually has a small upside: you don't need to figure out which cables to plug in, because they're all already there. Just route what you need and bundle the rest out of sight.
The low-noise fan is a genuine improvement over older CX models. Under typical gaming loads it stays quiet, only becoming noticeable under sustained heavy use. Installation is simple, with clear labelling on the connectors. For someone building their first PC and not wanting to overthink the PSU choice, this ticks the boxes without demanding much thought.
It's not the best value in this roundup (the CX750 offers more watts for less money), and it's not the most capable (the RM650e is far superior for a bit more). But as a beginner-friendly, no-fuss option from a trusted brand, it does the job well.
Pros
- Simple, beginner-friendly installation
- Reliable 650W output for mid-range builds
- Low-noise fan under typical loads
- Corsair quality and warranty backing
Cons
- Non-modular, so cable clutter is inevitable
- CX750 offers more watts for less money
- No ATX 3.1 or PCIe 5.1 support
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Proven Budget Workhorse
Price: £65.58 | Rating: ★★★★½ (4.6)
This is the older CX650 model, and it's been around long enough to have a substantial track record. Thousands of UK builders have used this PSU without issue, and that kind of real-world reliability data counts for something. It's 80 Plus Bronze, non-modular, and delivers 650W. Nothing fancy. Nothing cutting-edge. But proven.
The main reason it sits below the newer CX650 in this ranking is that the newer model has improved fan noise characteristics. The older CX650 can be a bit louder under load, which some owners have flagged in reviews. It's not a dealbreaker, but it's worth knowing.
At £65.58, it's priced similarly to the newer model. Honestly, if you're choosing between the two CX650s, the newer ASIN (B0CJRXX5WT) is the better buy. But if you find this one at a discount, it's still a perfectly capable PSU for a budget build. The ATX/EPS connectors cover standard motherboard and CPU power needs without any fuss.
Pros
- Long track record of reliability from real UK owners
- 650W covers most mid-range builds
- Corsair warranty and brand support
Cons
- Older design, fan can be louder than newer models
- Non-modular with no modern connector support
- Newer CX650 is a better buy at similar prices
Buy on Amazon£65.58
Entry Level
Price: £47.99 | Rating: ★★★★½ (4.7)
The CX550 sits at the bottom of this list, and that's not because it's a bad PSU. It's just the least compelling option when you consider what else is available for similar or slightly higher money. 550W is on the lower end for a gaming build in 2026. Pair it with a mid-range GPU and a modern CPU and you're leaving yourself with limited headroom.
The non-low-noise designation in the name is worth paying attention to. This model doesn't have the same fan profile improvements as the newer CX650. Under load, it can be noticeably audible. For a budget office PC or a very light gaming build with integrated graphics or a modest dedicated GPU, it's fine. For anything more demanding, the fan noise becomes a genuine annoyance.
At £47.99, it's priced accessibly. But here's the honest advice: for just a few pounds more, you can get the CX650 with 100W extra headroom and better fan behaviour. And for a bit more still, the CX750 offers 750W for under £50. The CX550 only really makes sense if your budget is extremely tight and your build is genuinely light on power demands.
Pros
- Low entry price for a Corsair-branded PSU
- 80 Plus Bronze certified
- Fine for very light or office builds
Cons
- 550W is limiting for modern gaming builds
- Fan noise is higher than newer CX models
- Better value options exist for slightly more money
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