FSP Hydro G 650 Power Supply Review

Transient Response Tests

Advanced Transient Response Tests

For details on our transient response testing, please click here.

In these tests, we monitor the response of the PSU in two different scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V and 0.5A at 5VSB) is applied for 200ms while the PSU works at 20 percent load. In the second scenario, the PSU is hit by the same transient load while operating at 50 percent load. In both tests, we use our oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain within the ATX specification's regulation limits.

These tests are crucial because they simulate the transient loads a PSU is likely to handle (such as booting a RAID array or an instant 100 percent load of CPU/GPUs). We call them "Advanced Transient Response Tests," and they are designed to be very tough to master, especially for PSUs with less than 500W capacity.   

Advanced Transient Response at 20 Percent

VoltageBeforeAfterChangePass/Fail
12V12.096V11.912V1.52%Pass
5V5.156V5.048V2.09%Pass
3.3V3.374V3.238V4.03%Pass
5VSB5.106V5.065V0.80%Pass

Advanced Transient Response at 50 Percent

VoltageBeforeAfterChangePass/Fail
12V12.055V11.958V0.80%Pass
5V5.132V5.025V2.08%Pass
3.3V3.337V3.219V3.54%Pass
5VSB5.066V5.029V0.73%Pass

During the first test, the +12V rail's deviation is quite high because the PSU operates its main switchers in PWM mode. In the second test, deviations on the same rail drop below 1 percent since the primary switches operate in FM mode. On the 5V and 5VSB rails, the voltage drops are controlled well. It's only on the 3.3V rail that we see a higher than 4 percent deviation during the first test. Even still, the rail's voltage remains above 3.2V during both tests.

Here are the oscilloscope screenshots we took during Advanced Transient Response Testing:

Transient Response At 20 Percent Load

Transient Response At 50 Percent Load

Turn-On Transient Tests

In the next set of tests, we measure the PSU's response in simpler transient load scenarios—during its power-on phase.

For the first measurement, we turn off the PSU, dial in the maximum current the 5VSB can output and switch on the PSU. In the second test, we dial the maximum load the +12V can handle and start the PSU while it's in standby mode. In the last test, while the PSU is completely switched off (we cut off the power or switch off the PSU by flipping its on/off switch), we dial the maximum load the +12V rail can handle before switching on the PSU from the loader and restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and 5.5V for 5V).

The 5VSB slope is very smooth, though we noticed a small bump during the second test. Finally, in the third and last test, the slope doesn't ramp up as smoothly. This won't cause any problems though, and the small spike before the rail's settle down is quite small. 

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14 comments
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  • Onus
    I see a Performance Per Dollar chart, but so far I've not been able to find the price of this unit. What is it?
  • sammy sung
    Hopefully a competitive price scheme. Looks awesome though, very nice aesthetic
  • Aris_Mp
    Quote:
    I see a Performance Per Dollar chart, but so far I've not been able to find the price of this unit. What is it?


    It is 90 bucks

    http://www.newegg.com/Product/Product.aspx?Item=N82E16817104200&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-VigLink2-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3821802&SID=il40akd6as0035wt00053
  • mrjhh
    I remember FSP being an OEM for older computer vendors like DEC, so they definitely aren't a newcomer to the field. I'm glad to see they know how to build a modern supply.
  • Onus
    IMHO FSP has always had a solid but "middle-of-the-pack" reputation; not anybody's first choice, but a lot better than a lot of the junk being sold. Even their Raider units that got very critical reviews were acceptable as budget units in light use. In big box PCs, I'd certainly rather see FSP than HEC or Bestec.
  • jeffunit
    I see "op amp amplifier" mentioned several times in the review.
    What is an "op amp amplifier"
    Doesn't amp stand for amplifier in this context, which expands to op amplifier amplifier?
  • anort3
    Odd naming scheme for a power supply. Hope it doesn't confuse anyone into thinking water goes well with it. :P

    Always good to see some of the larger if less well known manufacturers putting out quality units.
  • Aris_Mp
    Quote:
    What is an "op amp amplifier"


    short for operational amplifier
  • jeffunit
    Quote:
    Quote:
    What is an "op amp amplifier"
    short for operational amplifier


    op amp is short for operational amplifier.
    op amp amplifier is short for operational amplifier amplifier.
    You need to pay more attention to what is written.
  • turkey3_scratch
    Good performing power supply. In terms of voltages and ripple, beats the EVGA GS. I would never hesitate to recommend this unit, if it is priced well of course, which it already is not.
  • lunyone
    Had this been around $60 or so, it would be on my recommendation list. But at ~$90 I'm not as inclined to recommend it. Yes it is a good unit, but $90 just seems a bit steep for a 650w PSU. I'm more inclined to buy a $60-70 PSU for most of the builds that I do (all at least 80 PLUS Bronze rated). I know that this PSU is probably for those that have extra $ floating around or want more than just 80 PLUS Bronze certified PSU's.
  • sammy sung
    The GQ series seems hard to overturn, unless fully modular cabling is an absolute must for the consumer. I've never had an issue with semi-modular that made me cringe and exclaim that I should have forked out the extra $10-20. Aesthetics are more of a deciding factor for me, and realistically this edges out the HX series for that blue/white scheme, as far as I'm concerned at least.
  • Archaic59
    It's nice to have another unit to add to the short list of power supplies worth recommending. I'd like to see a 550 watt unit added to this line.
  • turkey3_scratch
    It runs for $81 now:

    PCPartPicker part list / Price breakdown by merchant

    Power Supply: FSP Group Hydro G 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($81.50 @ Newegg)
    Total: $81.50
    Prices include shipping, taxes, and discounts when available
    Generated by PCPartPicker 2016-03-05 21:53 EST-0500

    Which is comparable to the EVGA GS:

    PCPartPicker part list / Price breakdown by merchant

    Power Supply: EVGA SuperNOVA GS 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($79.99 @ Amazon)
    Total: $79.99
    Prices include shipping, taxes, and discounts when available
    Generated by PCPartPicker 2016-03-05 21:54 EST-0500

    Between the two, I'd take the FSP. I think I'm going to start making this FSP a common recommendation myself.