It seems that PSUs with a single +12V rail are recently becoming more and more popular, which is a trend present worldwide. The cause for this is likely the fact that more and more power-craving graphics cards are appearing on the GPU market, thus putting the +12V rail under considerable strain – just take Nvidia’s latest for an example. That makes PSUs with multiple +12V rails, but with a weaker power output, less desirable. This time, we’ve received a PSU from Cooler Master’s GX series, consisting of three models, with respective power outputs of 550, 650 and 750 W. The one we’ve tested is the strongest one, boasting a power output of 750 W.

This series is in general characterized by a five-year warranty period, as well as a very acceptable price, bound to appeal to those in need of a new PSU without a sizeable budget. The packaging itself doesn’t exactly give the impression of containing a particularly strong PSU, the box size being rather small and everything. The reason is that the box only contains the most essential of things, which comprises the PSU itself, mains power cable, four installation screws and a concise manual. This was the first step taken in order to save money. The PSU itself is not modular, which represents another such measure, without affecting the most important thing – performance. Cable length is sufficient to connect all the necessary cables, but not too great, which would create a mess inside the enclosure. The only cable which might have been better off if it were longer would be the 20/24-pin ATX connector cable, since additional length to it is always desirable when trying to “hide” it in larger casings. All PSUs in this series have the 80 Plus certificate, which guarantees efficiency of over 80% whatever the load. We were glad to see the on/off switch on the PSU, since it seems to have become somewhat of a trend to leave it out, even on more expensive models. The PSU can very well be used for SLI or Crossfire systems, since it has a total of four 6/8-pin PCIe connectors, which is, having the price of the PSU in mind, a very important plus for Cooler Master.

The PSU is cooled by a 12 cm fan, performing its duties as expected. The PSU remained moderately warm and very quiet even under strenuous loads. In order to test the PSU with a greater precision, we’ve used it to power a well-overclocked quad-core CPU, running at 4 GHz, as well as two overclocked ATI Radeon HD 5770 graphics cards in Crossfire mode. The testing was performed by stressing the components by running both Linx and 3DMark06 tests simultaneously. Idle tests were done on default clocks, while full load mode ran with all components overclocked as previously stated. As is evident from the test results, no significant voltage drop was noted. The only noticeable voltage drop was on the +12V rail. This voltage drop, albeit somewhat bigger, didn’t affect system stability, since the +12V value still remained well over the required 12 V, which is a good result. This also tells us that the PSU provides voltages a bit higher than declared when idle or under little load, but still well within ATX specification.