Corsair SF600 Power Supply Review

We recently evaluated Corsair's SF450, which left a good impression on us. Now it's time to test the family's flagship SF600, which can deliver 150W more power using exactly the same cable configuration.

By Aris Mpitziopoulos
published

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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 SF600's efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.

Image 1 of 4

Under normal loads, efficiency is very high. However, that's not the case under light loads, where the SF600 can't keep up with the competition (or the lower-capacity SF450).

Efficiency At Low Loads

In the following tests, we measure the SF600's efficiency at loads significantly lower than 10 percent of its 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 #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)Fan NoisePF/AC Volts
11.215A0.491A0.477A0.195A19.6168.38%169530.4 dB(A)0.935
11.977V5.048V3.342V5.055V28.68115.1V
22.461A0.990A0.986A0.395A39.7679.22%186031.2 dB(A)0.963
11.978V5.045V3.339V5.050V50.19115.1V
33.710A1.476A1.496A5.047A59.8583.87%198532.5 dB(A)0.975
11.977V5.042V3.336V5.047V71.36115.1V
44.941A1.984A1.978A0.789A79.7486.04%211534.6 dB(A)0.973
11.975V5.040V3.334V5.042V92.68115.1V

Higher operating temperatures prevent the fan's passive mode from kicking in. Noise output remains low in general, though we certainly couldn't say this is a quiet PSU like the previously-reviewed SF450. Efficiency takes a big hit in the 600W implementation of the same platform, which you can see during the first test where it drops below 70 percent.

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 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 #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
10.102A0.5272.22%0.101
5.058V0.72115.1V
20.252A1.2879.50%0.196
5.056V1.61115.1V
31.002A5.0681.88%0.370
5.048V6.18115.1V
42.502A12.5879.92%0.451
5.029V15.74115.1V
Image 1 of 2

The 5VSB rail is highly efficient. Corsair's SF600 loses only to its small brother, and just barely.

Power Consumption In Idle And Standby

In the table below, 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).

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Mode12V5V3.3V5VSBWattsPF/AC Volts
Idle12.018V5.052V3.348V5.059V6.900.615
115.1V
Standby0.070.011
115.1V
Image 1 of 2

Vampire power is very low with both voltage inputs.

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 (in RPM), and the delta between input and output temperature. The results were obtained at 37 °C (98.6 °F) to 47 °C (116.6 °F) ambient temperature.   

The next chart shows the cooling fan's speed (again, in RPM) 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 °C (98.6 °F) to 47 °C (116.6 °F) ambient temperature. 

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

Zero RPM mode doesn't last long, and the PSU's fan ramps up quickly, as you can see in the graph above. At loads in excess of 350W, the fan noise is between 43 dB(A) and 46 dB(A)—that's anything but quiet. Given the SF600's observed efficiency, we believe the fan profile could be relaxed a bit without affecting reliability.

Aris Mpitziopoulos
Aris Mpitziopoulos
Contributing Editor

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

38 Comments Comment from the forums
  • dudmont
    Are these small SFX designed for systems with ITX boards? I understand your complaints about the 8 pin cpu cables, but your complaints about PCIe cables doesn't make sense in light of the fact that no ITX board can handle more than one card. If you're using a micro-atx board, you can use a standard size PSU.
    Reply
  • powernod
    Wait a moment. Only 2 pci-e cables with 1 connector each one? That means that only one high-end GPU can be supported.
    Just like Aris said, what is the reason to go from the SF450 to the SF600, if you can't put another GPU?
    +150 watts only to feed SATA devices???!!
    Reply
  • LePhuronn
    A 600W PSU can drive a couple of high-end graphics cards and an overclocked CPU. But with only two PCIe connectors, the SF600 natively supports just one enthusiast-class GPU

    Yeah, because this PSU is intended to power top-end Mini ITX systems which can only run a single GPU. I thought that was obvious, or is there some standard requirement to review a component entirely in isolation without considering its application?
    Reply
  • LePhuronn
    Wait a moment. Only 2 pci-e cables with 1 connector each one? That means that only one high-end GPU can be supported.
    Just like Aris said, what is the reason to go from the SF450 to the SF600, if you can't put another GPU?
    +150 watts only to feed SATA devices???!!

    Headroom. I'm current running an original Titan and i5 2500 on Silverstone's ST45-G modualr PSU, and I'm only overclocking the Titan. However, I'm moving the Titan to a new build with a i7 6700K and I don't feel too comfortable pushing both the CPU and the GPU as far as they'd go with only 450W. I'd have no worries with a 600W.
    Reply
  • g-unit1111
    17905577 said:
    Are these small SFX designed for systems with ITX boards? I understand your complaints about the 8 pin cpu cables, but your complaints about PCIe cables doesn't make sense in light of the fact that no ITX board can handle more than one card. If you're using a micro-atx board, you can use a standard size PSU.

    Yes. They're designed to work in ultra compact cases like the Silverstone Raven RVZ01B, RVZ02B, as well as the Fractal Design Node 202. I think Corsair is even releasing their own ultra compact case at some point. But the trend is that cases are getting smaller, not bigger. Sure there will always be a market for ATX and EATX, but with Steam Box, you will start to see more of a demand for this type of case. With each generation from here on out, you'll see single cards be just as powerful as a dual card system. So you can get by with no SLI.
    Reply
  • turkey3_scratch
    Great Wall really is great. It's incredible that this compact unit blows most 600W units out of the water. It's not so much as "headroom" but if you take this PSU vs the SF450, and put that PSU on a machine with the same load, which will have the lower ripple and tighter voltage regulation? The SF600.
    Reply
  • jimmysmitty
    17905717 said:
    Wait a moment. Only 2 pci-e cables with 1 connector each one? That means that only one high-end GPU can be supported.
    Just like Aris said, what is the reason to go from the SF450 to the SF600, if you can't put another GPU?
    +150 watts only to feed SATA devices???!!

    A 980Ti is recommended, by nVidia, to have a 600W PSU and that is for the stock 1000MHz speed 980Ti. If we consider the fact that the majority of 980Tis come stock with 10-20% overclocks then a 600W SF PSU would be preferable for a high end ITX build. I can tell you a lot of people throw 980Tis into ITX builds.
    Reply
  • turkey3_scratch
    Also let's not forget peak efficiency at 50% of a power supply's capabilities, so the SF600 is ideal for that.
    Reply
  • RedJaron
    Peak efficiency may be around 50% load, but you're forgetting that this is an 80 Gold unit. While it's at least 90% efficient at 50% load ( the graphs looks to be a bit above that ), it's still ( at least ) 87% efficient at 90% load. You're only losing about 5% efficiency between the two here. That only means it draws a few more watts from the wall. Delivery inside the case remains unchanged.

    GPU mfrs' recommended PSU capacities are always inflated to compensate for the mediocre ( or worse ) PSUs that flood the mainstream and OEM space. A 980 Ti will pull at most 250W - 275W, depending on OC, during a heavy gaming load. Torture tests can go above 300W, but no one mines with an ITX box. Adding the 130W you'll see from the rest of a typical i7 system, you'd rarely see this go above 400W. That's an 88% load on a 450W PSU. Tight, but certainly not risky or dangerous. As I constantly remind people, my i7 + 290X test bed runs just fine on a 500W PSU, and that GPU is a lot hungrier than the 980 Ti.

    The only legitimate use for this PSU, with it's 600W but very limited cables, that I can think of is a heavily OC'd ITX gaming box built in a case that requires an SFX PSU. I can't find a single Z170 or X99 ITX board that has more than an 8-pin CPU power connector, so the PSU's limitation there shouldn't matter. Split the load 300W for the GPU, 250W for the CPU and rest of the system and you duck in just under the power limit. But again, that only makes sense if you MUST use a SFX PSU. Plenty of small cases support full size ATX units, where you have a lot more selection.

    This feels as though either Corsair is trying to fleece some customers into spending more than necessary or they got lazy in expanding a product line by increasing capacity without also taking the trouble to re-tool the cabling.
    Reply
  • Aris_Mp
    In my opinion a 600W PSU (even an SFX one) should have 4x PCIe connectors, because VGAs like the GTX970 and GTX980 consume 160W-200W at worst case scenario, so a couple of them can be easily supported.
    Reply