FSP Hydro PTM 750 W Review

Name: FSP Hydro PTM 750 W
Brand: FSP

crmaris

on Nov 9th, 2017,

in Power Supplies.

Manufacturer: FSP

Protection Features Evaluation »

Ripple Measurements

You will see the ripple levels we measured on the rails of the HPT750M in the following table. The limits are, according to the ATX specification, 120 mV (+12V) and 50 mV (5V, 3.3V, and 5VSB).

Ripple Measurements - FSP HPT750M
Test	12 V	5 V	3.3 V	5VSB	Pass/Fail
10% Load	19.3 mV	7.0 mV	7.6 mV	11.0 mV	Pass
20% Load	18.4 mV	5.9 mV	6.4 mV	16.6 mV	Pass
30% Load	18.4 mV	6.2 mV	6.8 mV	18.6 mV	Pass
40% Load	19.5 mV	6.8 mV	7.4 mV	22.6 mV	Pass
50% Load	20.0 mV	6.8 mV	7.1 mV	19.5 mV	Pass
60% Load	22.0 mV	7.7 mV	8.4 mV	17.9 mV	Pass
70% Load	23.2 mV	8.2 mV	7.4 mV	15.7 mV	Pass
80% Load	21.4 mV	9.1 mV	9.0 mV	20.6 mV	Pass
90% Load	22.3 mV	9.7 mV	11.0 mV	20.9 mV	Pass
100% Load	23.7 mV	12.9 mV	11.7 mV	23.4 mV	Pass
110% Load	25.2 mV	12.7 mV	12.2 mV	22.3 mV	Pass
Crossload 1	19.9 mV	8.6 mV	10.1 mV	8.5 mV	Pass
Crossload 2	24.1 mV	13.4 mV	11.0 mV	15.5 mV	Pass

Ripple suppression is excellent on the +12V, 5V, and 3.3V rails and satisfactory with 5VSB. Very good performance, it is also achieved without additional caps on the cables.

Ripple at Full Load

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

Ripple at 110% Load - 115 V

With 230 V, ripple suppression is fine throughout, but with 115 V and under the same high operating temperatures, there were some spikes on all the rails. The lower efficiency levels with 115 V, especially with the 110% load, and the increased energy losses apparently lead to higher internal temperatures, which are responsible for these spikes. However, with the PSU operating outside of its nominal capacity range, this can't be called a design flaw.