FSP Hydro PTM 650W PSU Review: Clean, Quiet Power for Mid-Range PCs

Ripple Measurements

To learn how we measure ripple, please click here.

The following table includes the ripple levels we measured on the HPT650M’s rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).

Test12V5V3.3V5VSBPass/Fail
10% Load28.8mV4.9mV4.7mV11.9mVPass
20% Load19.8mV4.6mV5.0mV13.8mVPass
30% Load17.5mV5.4mV5.4mV17.5mVPass
40% Load18.8mV5.5mV5.3mV22.4mVPass
50% Load19.7mV6.5mV5.6mV23.4mVPass
60% Load21.6mV7.1mV6.1mV17.3mVPass
70% Load21.6mV7.3mV6.6mV18.0mVPass
80% Load22.9mV8.3mV8.2mV16.0mVPass
90% Load23.8mV8.9mV8.6mV17.2mVPass
100% Load25.6mV8.9mV8.9mV19.6mVPass
110% Load26.9mV9.6mV9.6mV18.4mVPass
Cross-Load 119.0mV7.3mV9.3mV6.4mVPass
Cross-Load 225.9mV7.6mV5.7mV7.6mVPass

All of the rails deliver clean voltages. It is nice to see such good results from a power supply that doesn't rely on extra filtering capacitors in its cables.

Ripple Oscilloscope Screenshots

The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the screen, the bigger the ripple/noise. We set 0.01 V/Div (each vertical division/box equals 0.01V) as the standard for all measurements.  

Ripple At Full Load

Ripple At 110-Percent Load

Ripple At Cross-Load 1

Ripple At Cross-Load 2

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  • AnimeMania
    Is there a reason why they put the word "Hydro" in the title?
  • SR-71 Blackbird
    Thanks Aris , nice review , much appreciated.
  • average joe
    they want to market it as water cooler compatible... yeah i know..
  • average joe
    there used to be some really crappy power supplies in the world but now most of them are fine. you had to be really careful or you burn up everything. that doesn't happen anymore.
  • average joe
    there really only three companies that make PSU now and they all just badged for different brands. one might insist on using higher grade but its still a superflower.
  • average joe
    rosewill capstones are usually superflower and 1/2 the money
  • police_leduc113
    Even so, for guys like me who only use a "normal pc" without OC, this one will do just fine right? Cause i got it from black friday for the right price, while Seasonic stuff are insanely expensive in my country
  • SR-71 Blackbird
    Some of the Rosewill Capstones , don't get good reviews from buyers , I avoid them.
  • Co BIY
    POLICE_LEDUC113 - Yes, This is a better than average power supply. Not the absolute best but priced in the US with the absolute best. If you got it at good price compared to the competition then it will do well for you.