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Seasonic G-Series 450W PSU Review

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.

Our Verdict

Seasonic's G-450 is a low-capacity PSU with very good build quality and good overall performance. But the unit could be improved if it featured a quieter operation, offered higher efficiency and sold for a lower price.

For

  • Compact dimensions • Efficient at light loads • Full power at 46 degrees C • Hold-up time • Ripple suppression • Quality electrolytic caps • Warranty

Against

  • Noisy under stress • Not very efficient with normal loads • Price

Introduction

Seasonic is a well-known company in the PSU market; in addition to retail sales, its platforms are also used by many other companies, including Antec, Corsair, EVGA and Fractal Design. One of Seasonic's budget Gold-rated lines is the G series, which consists of five products with capacities ranging from 360 to 750W. Today we're looking at the G-450, which, as its model number implies, offers up to 450W of capacity.

All G-series power supplies use a semi-modular cabling design, have compact dimensions and are cooled by a 120mm fan. In addition, they are backed by a five-year warranty, which is rather long for the standards of this category. Seasonic claims that the performance of its G-series PSUs is top-notch, and we believe the company since we've tested a number of models in this line, including units based on the same platform. The results were very good in all cases.

The G-450 is a high-quality low-capacity PSU able to cover not only entry-level systems but also mid-range ones with respectable GPUs (thanks to its two auxiliary PCIe connectors). Power supplies like this are popular with enthusiasts who know they don't need massive output, only to use a fraction of it. Typically, lower-wattage PSUs achieve significantly higher efficiency at light loads compared with more powerful PSUs, so if your system's energy needs are low, then you should avoid buying a high-capacity supply. Otherwise, you'll pay more for the unit itself and incur increased operational costs compared to a less-powerful model offering the same efficiency characteristics. On the other hand, if you plan to add a second graphics card, you'll need a power supply with at least four PCIe connectors and 500W+ capacity. The G-450 would fall short in that case.

Specifications

Besides 80 PLUS Gold efficiency, the G-450 is also Haswell-ready and can deliver its full power continuously at up to 50 degrees Celsius (122 degrees Fahrenheit) ambient temperature. This is a clear indication that it is based on a solid platform with good components that are able to withstand tough conditions. The PSU offers all necessary protections, including OCP (over-current protection), even though it sports a single +12V rail. We typically don't see OCP in PSUs with one +12V rail; Seasonic most likely added this protection because of the unit's low capacity.

Cooling is handled by a 120mm double ball-bearing ADDA fan. It's a good-quality cooler that should work flawlessly for many years. And even though the price is on the high side, we believe the build quality of this product justifies it.

Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps20203730.3
Watts10044412.53.6
Total Max. Power (W)450

The single +12V rail can deliver the PSU's full power alone; it has enough amperage to feed a high-end GPU. The minor rails are strong for a modern system that is covered by a 450W power supply, and the 5VSB rail has the typical capacity for a contemporary PSU.

Cables & Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)
ATX connector 20+4 pin (550mm)11
4+4 pin EPS12V (570mm)11
Native Cables
6+2 pin PCIe (610mm)22
SATA (400mm+115mm+115mm+115mm)14
SATA (300mm+115mm)12
Four-pin Molex (400mm+120mm+120mm)13
Four-pin Molex (300mm+120mm)12
FDD Adapter (+110mm)11

This unit has the typical cable/connector configuration for a respectable low- to mid-capacity PSU. Seasonic equips it with a single EPS connector and a pair of PCIe connectors, through which the G-450 can easily deliver its full power. In addition, six SATA and five four-pin peripheral Molex connectors are more than enough for this category.

Overall, cable length is adequate with one exception: the EPS cable, which in our opinion should be at least 60 centimeters in length. All connectors use 18-gauge wires, which are recommended by the ATX spec.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

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  • 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