SilverPower SP-SS650Manufacturer: SilverPower
UK Price (as Reviewed): £66.11 (inc. VAT)
US Price (as Reviewed):
SilverPower is the budget brand of Tagan, and its power supplies usually have captive rather than modular cables.
The SP-SS650 maintains this status quo with its captive cables, and unlike the Tagan PipeRock II TG680-BZII
, it isn’t endowed with an eye-wateringly bright blue LED. The SP-SS650 is based on an old Seasonic design, so we had high hopes for a stable set of rails and good power efficiency.
One curious aspect of the SP-SS650 is SilverPower’s claim that it has four 12V rails, each rated at 18A with a maximum combined output of 52A. However, we could only locate two 12V rails on the PCB, which are configured so that 12V1 powers the CPU and disk drives, while 12V2 supplies the motherboard and PCI-E power cables – one 6+2-pin and one 6-pin. The 3.3V rail is rated at 24A, the 5V rail at 30A, the -12V rail at 0.8A and the 5VSB rail at 3A. The interior is cooled by a relatively quiet 120mm fan.
All the rails output a very stable voltage at 50 per cent load, while proving a commendable 86 per cent efficient. At full load, the efficiency started off the same, but by the end of our 30-minute stress test, it had dropped to 85 per cent. This isn’t a bad result, however, and it’s
still better than three of the other PSUs in this Labs test. The output from all the rails was within the limits of the ATX spec at full load, although both the 5V and 5VSB rails dropped to 4.77V – a mere 0.02V above the minimum 4.75V required by the ATX spec.
While the SP-SS650 lacks any outstanding features, its rails were stable during our testing period. The 120mm fan is also reasonably quiet, 650and the PSU doesn’t waste much electricity converting 230V AC down to the 3.3V, 5V, 12V and -12V DC required by your PC. The SP-SS650 also has a very low price – significantly less than most branded PSUs. As such, if you’re on a tight budget then it’s definitely worth investigating.
Click to enlarge
Seasonic X-650Manufacturer: Seasonic
UK Price (as Reviewed): £104.05 (inc. VAT)
US Price (as Reviewed): $159.99 (ex. Tax)
Seasonic’s own brand of PSUs and the power supplies that it makes for other brands have probably won more awards that any other. In short, Seasonic PSUs are usually a great buy, although they’re often quite expensive, as in the case of the £192 M12D-850. The Seasonic X-650 is no exception; despite being rated at 650W like many other PSUs on test, it retails at a hefty £105.
The X-650 has just one 12V rail rated at 54A, which should be enough for an overclocked PC packed full of drives and a couple of high-end graphics cards. The latter is possible thanks to the X-650 having four 6+2-pin PCI-E connectors. There are also eight SATA and eight Molex modular connectors, so the X-650 provides plenty of choice for drives.
Stability is more important, though, and the X-650 had no problems in this area. It passed all the tests thrown at it by the Chroma machine, with all its outputs remaining well within the limits of the ATX spec. What was most impressive, though, was its efficiency. This topped out at 89 per cent at 50 per cent load, and a remarkable 90 per cent at full load.
It was so cool-running as a result of this awesome efficiency that its 120mm fan only needed to start spinning after a few minutes at 100 per cent load. This indicates that it has an awesome trick up its sleeve – in many systems, the X-650 will be silent, as the fan doesn’t even spin up under 50 per cent load (300W).
Over the course of a few years, the Seasonic X-650 could pay for itself, thanks to its high power efficiency. Compared with PSUs of just a few years ago, you’d be using up to 70W less for the same power compared with a five-year-old 650W PSU. Even compared with other PSUs in this Labs test, there would be significant gains to be had if you used your PC for more than 15 hours a week or ran folding 24/7. That said, it would take several years for it to be better value than the Antec TruePower New TP-650
Click to enlarge