Seasonic G-Series 450W PSU Review

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Seasonic's G series consists of reliable, high-performance PSUs. Today, we're reviewing the G-450 with 450W capacity, which features a semi-modular cabling design.

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Efficiency, Temperature And Noise

Efficiency

Our efficiency testing procedure is detailed here.

Using the results from the previous page, we plotted a chart showing the Seasonic G-450's efficiency at low loads, and loads from 10 to 110 percent of the PSU's maximum rated capacity.

Image 1 of 4

With normal loads, efficiency wasn't as high as we expected from this platform. Most likely, the increased Rds (on) resistance of the APFC and main switchers are to blame. Under lighter loads, the efficiency ratings were better.

Efficiency At Low Loads

In the following tests, we measure the efficiency of the Seasonic G-450 at loads significantly lower than 10 percent of the device's maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dialed were 20, 40, 60 and 80W. This is important for representing when a PC is idle, with power-saving features turned on.

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Test #12V5V3.3V5 VSBPower(DC/AC)EfficiencyFan SpeedFan NoisePF/AC Volts
11.191A0.491A0.475A0.194A19.61W69.59%625 RPM27.8 dBA0.935
12.211V5.082V3.364V5.036V28.18W115.1V
22.411A0.980A0.981A0.395A39.68W79.90%625 RPM27.8 dBA0.972
12.202V5.078V3.359V5.028V49.66W115.1V
33.635A1.466A1.490A0.595A59.75W83.86%625 RPM27.8 dBA0.983
12.194V5.073V3.354V5.019V71.25W115.1V
44.857A1.973A1.969A0.794A79.76W86.03%645 RPM28.0 dBA0.993
12.187V5.069V3.348V5.008V92.71W115.1V

Under light loads, the PSU is very quiet, On top of that, it achieves high efficiency.

5VSB Efficiency

The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher efficiency with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.

We will take four measurements: one each at 100, 250 and 1000mA, and one with the full load the 5VSB rail can handle. 

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Test #5VSBPower (DC/AC)EfficiencyPF/AC Volts
10.101A0.51W76.12%0.132
5.042V0.67W115.1V
20.251A1.26W77.78%0.252
5.037V1.62W115.1V
31.002A5.03W79.21%0.410
5.020V6.35W115.1V
42.502A12.47W76.83%0.476
4.985V16.23W115.1V
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Overall, the 5VSB rail registered good efficiency levels, although it didn't manage to pass the admittedly hard 80 percent mark in any of the tests we conducted.

Power Consumption In Idle And Standby

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Mode12V5V3.3V5VSBPower (AC)PF/AC Volts
Idle12.276V5.088V3.369V5.044V8.55W0.694
115.1V
Standby0.05W0.011
115.1V
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In the table above, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the PSU is in standby mode (without any load, at 5VSB).

Vampire power is very low at mere a 0.05W. With 230V, input is kept quite low as well, at 0.11W.

Fan RPM, Delta Temperature And Output Noise

Our mixed noise testing is described in detail here.

The first chart below illustrates the cooling fan's speed (RPMs), and the delta between input and output temperature. The results were obtained at 37 to 46 C (98.6 to 114.8 F) ambient temperature.   

The next chart shows the cooling fan's speed (RPMs) and output noise. We measured acoustics from one meter away, inside a small, custom-made anechoic chamber with internals completely covered in sound-proofing material (be quiet! Noise Absorber kit). Background noise inside the chamber was below 18 dB(A) during testing, and the results were obtained with the PSU operating at 37 to 46 C ambient temperature. 

Image 1 of 2

The following graph illustrates the fan's output noise over the entire operating range of the PSU. The same conditions of the above graph apply to our measurements, though the ambient temperature was between 28 and 30 C (82.4 to 86 F). 

At very low loads, the PSU's fan is quiet. With typical loads of up to 250W, its noise starts to be noticeable. And with higher loads, the PSU starts to be quite noisy.

Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

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18 Comments Comment from the forums
  • InvalidError
    0.4 ohm Rdson is not that bad for primary-side FETs where switching losses tend to be much worse than on-losses.

    Also, FETs with better on-resistance usually have larger gate charge, which means you end up needing more gate drive power to achieve the same switching performance. Saving 3W on full-load on-losses does not sound as good if it costs you 2W in gate drive regardless of load.

    Using FETs with lower on-resistance does not necessarily improve overall efficiency by much.
    Reply
  • TechyInAZ
    Good read. I personally have the 550W version of that PSU and it works very well. Very quiet too, however my entire system doesn't go beyond 350W at max load.

    BTW...The 550W version is usually only $3-$5 more than the 450W. I've never seen the price change either, so it is a bit silly to buy the 450W version if the 550W is always only $5 more.
    Reply
  • Dunlop0078
    I also have the 550watt version, its been going strong for about two years now its very quiet even under load I think I pull about 450watts or so when I have all my overclocks applied. It has been totally stable not a single problem with my PC or the psu since I bought it.

    However I think the price should be lowered a bit for the 550watt version because now it has to compete with the likes of the EVGA 550 G2 which is about the same price but it seems to perform a bit better and comes with a 10 year warranty.
    Reply
  • TechyInAZ
    16760449 said:
    I also have the 550watt version, its been going strong for about two years now its very quiet even under load I think I pull about 450watts or so when I have all my overclocks applied. It has been totally stable not a single problem with my PC or the psu since I bought it.

    However I think the price should be lowered a bit for the 550watt version because now it has to compete with the likes of the EVGA 550 G2 which is about the same price but it seems to perform a bit better and comes with a 10 year warranty.

    10 year warranty!!?? I've been using EVGA graphics cards for years now, I think ill start buying EVGA PSUs now. :D
    Reply
  • Dunlop0078
    16760449 said:
    I also have the 550watt version, its been going strong for about two years now its very quiet even under load I think I pull about 450watts or so when I have all my overclocks applied. It has been totally stable not a single problem with my PC or the psu since I bought it.

    However I think the price should be lowered a bit for the 550watt version because now it has to compete with the likes of the EVGA 550 G2 which is about the same price but it seems to perform a bit better and comes with a 10 year warranty.

    10 year warranty!!?? I've been using EVGA graphics cards for years now, I think ill start buying EVGA PSUs now. :D

    Actually im wrong on that its a 7 year warranty for the 550watt model (still very good in my opinion) the 750watt g2 and above have the 10 year.
    Reply
  • 10tacle
    I know Seasonic is good and an OEM to PSUs for Corsair and whatnot, but I was an unlucky one. My 620W S12II crapped out on an older backup rig after about a year of light use, maybe 250 hours. Unfortunately I voided the 5-year warranty when I had to break the screw seal and open it to get a screw out that accidentally fell in (PC was unplugged when that happened). I figured I'd never need to worry about dealing with a warranty RMA anyway since in nearly 20 years of PC building I've never had one die early on me. WRONG.
    Reply
  • InvalidError
    16760681 said:
    I figured I'd never need to worry about dealing with a warranty RMA anyway since in nearly 20 years of PC building I've never had one die early on me. WRONG.
    Murphy strikes again!
    Reply
  • Blueberries
    This PSU isn't bad but I don't see why anyone would want to pay in the $70's for it when there are gold-- almost platinum rated Leadex PSUs for $80-$90.

    The build quality is what I've come to expect from SeaSonic. Very well built with mostly Nippon Chemi-Con capacitors. Rubycon is also a good brand, and I like to see Infineon MOSFETs in PSUs. This PSU should last forever but isn't very efficient compared to similarly-priced competition.
    Reply
  • turkey3_scratch
    16760497 said:
    16760449 said:
    I also have the 550watt version, its been going strong for about two years now its very quiet even under load I think I pull about 450watts or so when I have all my overclocks applied. It has been totally stable not a single problem with my PC or the psu since I bought it.

    However I think the price should be lowered a bit for the 550watt version because now it has to compete with the likes of the EVGA 550 G2 which is about the same price but it seems to perform a bit better and comes with a 10 year warranty.

    10 year warranty!!?? I've been using EVGA graphics cards for years now, I think ill start buying EVGA PSUs now. :D

    Yeah, aside from the fantastic quality, that was another reason I purchased the G2 over any other PSU.
    Reply
  • tsnor
    "... Seasonic doesn't use a fully modular design in its G series to keep production costs low. Of course, it would be nice if the company changed its strategy and went all-modular on its G-series models since many competing PSUs are, in fact, fully modular...."

    Or maybe they
    (1) know that people will always use the permanent cables that power the MB
    (2) know that two less connectors is a good thing for product reliability
    (3) want to ship a product for people like me that prefer this configuration to a fully modular configuration
    Reply