Zalman ZM500-RS Power Supply Review

Conclusions

If you bought this power supply you won’t face any problems. However, we were expecting more from it, especially because we are talking about a power supply that costs USD 100.

Ripple and noise level at +12 V rails was too high while the power supply was delivering 500 W, at 105 mV, too close to the 120 mV limit. And we didn’t like the cable configuration very much. Although it will probably fit the needs of most users looking for a 500 W product, we’d prefer to see the two video card auxiliary power connectors using individual cables instead of being attached to the same cable and one more SATA/peripheral power connector on each cable, for a total of six connectors from each type instead of only four.

Efficiency was high when we pulled up to 80% of the labeled power (i.e., up to 400 W), but dropped to a little bit above 80% when we pulled the full 500 W from this unit. This power supply is 80 Plus Bronze certified, meaning that it should present 82% efficiency at full load, but as we have exposed on our Can We Trust the 80 Plus Certification? article, Ecos Consulting, the company behind the 80 Plus certification, uses an unrealistic room temperature to test power supplies, and efficiency drops with temperature. Interesting enough on the product box it says that this unit has the standard 80 Plus certification, the 80 Plus Bronze information is available only on the manufacturer website.

But what really kills ZM500-RS is its price. It is unbelievable expensive for a 500 W product. You can buy a 750 W power supply from Seventeam (ST-750P-AF) for the same price and get similar performance, higher number of cables and higher wattage!