Articles: Cases/PSU
 

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Specifications

The specifications are very close to those of the FSP Epsilon Pro 85PLUS 700 except that the Zalman can yield less than its full output power via the +12V rail while the load capacity of the other rails is somewhat higher.

Anyway, like the native FSP, the Zalman cannot deliver the whole specified output power via the three main rails. The specified 700 watts is arrived at by adding 24.6 watts from the standby source and the -12V voltage.

The Zalman ZM700-GT complies with the 80 PLUS Bronze requirements.

UPS Compatibility

Working together with our APC SmartUPS SC 620, the PSU was stable at loads up to 359 watts when powered by the mains but couldn’t switch to the UPS’s batteries even at 280 watts, just like its FSP-branded cousins.

Cross-Load Voltage Stability

The Zalman ZM700-GT did better in this test than its FSP counterpart:

The +12V voltage is mostly within 3% of the required level except for very small areas of highly misbalanced loads.

The +5V and +3.3V voltages are also stable in the typical load range.

So, the Zalman ZM700-GT is quite good in this test for a PSU without dedicated voltage regulation.

Output Voltage Ripple

The high-frequency voltage ripple is strong on the +3.3V and +5V rails but never exceeds the permissible limits. The native FSP products were better in this respect. The ripple is weaker on the +12V rail.

The low-frequency voltage ripple is weak on the +5V and +12V rails.

Temperature and Noise

The fan is yet another different from the FSP Epsilon. Instead of a noisy Power Logic, the Zalman uses a Yate Loon D12SH-12 (120 mm, 2200 RPM). We’ve seen this fan in the Corsair CX600 already.

Alas, the quieter fan is let down by the poor regulation algorithm. The impeller accelerates right away, reaching over 1900 RPM at full load, which is 450 RPM higher than the fan speed of the FSP Epsilon Pro 85PLUS 700. The start speed of the Zalman’s fan is as high as 1000 RPM – the FSP only reached it at a load of 500 watts.

Thus, the Zalman ZM700-GT is anything but quiet.

Efficiency and Power Factor

The Zalman ZM700-GT is 85.2%, 87.5% and 84.7% efficient at the reference loads of 20%, 50% and 100%, which complies with the 80 PLUS Bronze specs. The peak efficiency of 88% was observed at a load of 371 watts.

The power factor is higher than 98%, which is typical of PSUs with active power factor correction.

Standby Source

The standby voltage is normal.

Summary

The Zalman ZM700-GT is a good alternative to the FSP Epsilon series in electrical parameters, but its fan regulation algorithm is inadequate.

 
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