Power Supply The Seasonic SSP-300SUG fully modular 150mm FlexATX PSU

[iFreilicht]

Just received this unit today and thought I would take a look at it.
I won't actually turn it on until I get the prototype parts for Brevis S, but I got pretty excited just looking at it.

Here are my first impressions:


Thanks for reading!

 

[jeshikat]

Great overview of the unit!

The fan connector looks identical to the JST XH series: http://www.jst-mfg.com/product/detail_e.php?series=277

The small fan connectors used on video cards and power supplies are typically either from the XH or PH line from JST, or in this case, an interchangeable version from a different vendor.

 

[iFreilicht]

Thanks, added it to the description of the last picture!

 

[iFreilicht]

So after using the unit in my rig for over a month now, I did a bit of stress testing today.
My setup is a short GALAX GTX970 OC, an i7-4770T (45W TDP) and 16GB of G.Skill Value F3-1600C11S-8GNT RAM, so maximum power consumption should be well below the 300W of this PSU.

Until now, I was relatively happy with the unit, but I never exhibited massive loads on it. I played Rocket League for five hours straight, no problem, but that's not particularly hard on the GPU, it's a well optimised Unreal Engine 3 game.

During that time it was relatively quiet. As a matter of fact, it was about as loud as the the GPU fan during gaming, but with a somewhat higher pitch. Pretty reasonable in my eyes. The GPU load was at 40 to 55% , power consumption between 55 and 65%, as observed with HWMonitor.
During that time, the LiHeat riser was covering the top vents of the PSU, which didn't affect the noise at all.

Onto the tests: First, I made sure that the vent holes weren't covered to make sure the PSU didn't get suffocated.

Then I did the first test, GPU-only running Heaven Benchmark 4.0 on extreme presets. GPU load and power consumption were at 100%, power consumtion even got to 105% at some point.
And boy did the PSU suddenly get loud. Not quite a mini-jet engine, but reasonably close, at least with my rig sitting directly in front of me. Still perceivable with headphones on, though my headphones are very open to external noise.

Not really chuffed by that, but it did run well, and after half an hour I decided that the test was passed.

For the second test I wanted to go all-in, so Prime95 on the CPU for a few minutes until temps and noise stabilised and then Heaven on top of that. The CPU got into up to 65W of Package power consumption. Unsurprisingly, this additional load caused the PSU to spin it's teeny fan even louder, definitely over the acceptable level, but what did suprise me was the fact that after 30 seconds of combined Heaven and Prime, the whole PC shut off in an instant.

Not at all happy with that result. I know Prime puts an unrealistic load on the CPU, but I would've never thought that the SSP-300SUG couldn't handle that. I guess my system does draw more than 300W in this case. Unfortunately, I have no way of testing that.

 

[QinX]

Not at all happy with that result. I know Prime puts an unrealistic load on the CPU, but I would've never thought that the SSP-300SUG couldn't handle that. I guess my system does draw more than 300W in this case. Unfortunately, I have no way of testing that.

Too bad the fan is that loud, unfortunatly one of the concessions you have to make with FlexATX I think. What kind of 80PLUS rating does the SSP-300SUG have? Perhaps in the future a noise reduction can be gained from stepping that up.

With H2O-Micro I had a GTX970 + 4670 + 16GB ram and with Prime and Furmark I've hit 285W AC and I believe I've hit 300W AC on occasion. So you're likely to have hit the upper end of what it was designed for, maybe around 250W DC
I had a higher TDP CPU, but a reference 970, so that might cancel eachother out, I'm not sure what the impact of my Thin-ITX system has compared to ITX , mSATA - SODIMM - onboard DC conversion etc.

 

[iFreilicht]

It is indeed one of the things FlexATX doesn't excel at, but the loudness I experienced isn't really acceptable in my eyes. The workaround will be to get stronger and more efficient PSUs, those should be less loud under the same load. Of course there's also the possibility of a fan-mod. The 80x10mm fan Scythe uses on the Kozuti would be perfect, but it's not available separately.

What kind of 80PLUS rating does the SSP-300SUG have?

This unit is rated 80Plus Gold, so quite decent already.

With H2O-Micro I had a GTX970 + 4670 + 16GB ram and with Prime and Furmark I've hit 285W AC and I believe I've hit 300W AC on occasion. So you're likely to have hit the upper end of what it was designed for, maybe around 250W DC

Isn't maximum load always given in Watts on the DC rails? The SSP-300SUG is claimed to have a total maximum power draw of 300W on the 12V rail alone, so you'd think that 250W on all rails combined wouldn't be a problem. 300W total is also a limit, though.

I don't think the issue is the power draw itself, but overheating. I don't know how it's implemented, but if there's a current limiter inside the unit, that should probably kick in as soon as that current limit is reached, not 30 seconds in.

 

[Hahutzy]

I just got done testing the 300SUG, and... it ran without crashing at all.

Tested using:
i5-4440s + Noctua L9i
Gigabyte 970 ITX
Mushkin 240GB SSD
2 sticks of 4GB ram

Tests I did:

Unigen Heaven, extreme settings x1
3DMark Firestrike x1

30-min torture test:
Start with prime-95, Inplace Large FFT 4 threads
After 10-minutes, Start furmark on default settings (8x MSAA 1280x720)



It all ran fine. In fact the fan noise was less whiny than the FSP 400W.

Color me confused

 

[iFreilicht]

That is very strange, but Furmark is detected by quite a few GPUs and they throttle down a bit, isn't it. I'll test with furmark too, once I get home.
Did you happen to check the power consumption your CPU was reporting during this test?
It also looks like your 970 is clocking lower by about 100Mhz than mine, but I'd have to check again. Either my unit is faulty, or we're operating at the exact edge of the maximum load this PSU can take.

It's true that the fan isn't very whiny, for such a small a fan it has relatively low pitch and it's mostly air-noise you're hearing, but it's still very loud. I'd say a little louder than an old Xbox 360, which wasn't exactly quiet either.

 

[Hahutzy]

Yea FurMark downclocks it. Despite that though, both Furmark and GPU-Z reports that the 970 was power-limited during the run, not utilization-limited. Meaning it's drawing the most power it can.

I did not record the CPU power usage, but when I checked in HWMonitor, it was around 48W Package, 37W IA Cores, 9W Uncore. Don't remember the other entries.

Your card's Base and Boost clocks are 50Mhz higher than mine, so the 100Mhz difference makes sense.

 

[iFreilicht]

48W Package

Mine reported 65W, so it could be that those 17W made the difference.

 

[Hahutzy]

That may be it. I just reran prime95 a couple of minutes and it never reaches past 48W.

That sucks if it really comes down to CPU choice for this PSU...

 

[Kmpkt]

got my hands on one of these and was thinking that something like HDPlex modular ATX bridge would be really nice to modularize the unit. What I had in mind would be a 24 pin input on one side to plug into the PSU and then modular connectors on the other side of the PCB for 24 pin ATX, 8 pin EPS, 8 pin PCIe and a 4 pin for SATA etc. Anyone interested in pursuing this solution? I've already started talking to Larry at HDPlex about feasibility.

 

[iFreilicht]

That sounds like an interesting idea in theory, but how would those connectors be oriented and where would you place them? To me it sounds like you're thinking about a stiff PCB solution, and if that's the case you only have space in front of the PSU to put those connectors, effecticely making the PSU quite long.
Or do you have something else in mind?

 

[Kmpkt]

Yeah that is basically it. If you had the 24 pin basically run through the PCB so it is directly vertical from where it is now then you could have an entire other row of connectors parallel to the 24 pin that included both 8 pins as well as the 4 pin for SATA etc. It would add at most 1 cm to the length of the PSU and wouldn't necessarily need to add height. Considering every other Flex ATX solution on the market has a fat bundle of cables that effectively lengthen the psu's space requirement by a couple centimetres at least, I think this is a pretty elegant solution.

 

[Hahutzy]

I think this is a more ideal solution than to ask SeaSonic to OEM different harnesses.

Although I'm having some doubt that it will not add height at all.

Personally though, I would say adding 1cm length is better than adding any height, because most FlexATX psus come with a trailing bracket anyway, and that's an extra ~1cm.

 

[iFreilicht]

I think you need to factor in a little more than just 1cm, closer to 16mm as you need space for the locking hooks, but other than that it's a relatively sound idea. How many pins would the connector for the ATX24pin harness have in this scenario? I'd say 12 is the lower limit.

 

[Kmpkt]

As you can see by the photos below, you'd essentially be looking at about 17cm long and no change in overall height. By coincidence this is exactly the length of an ITX motherboard which is as far as I'm concerned perfect.

 

[Hahutzy]

The problem with that is, after you connect the cables, they will all have to have clearance above the PSU.

The current SSP300 doesn't need clearance above it even after connecting the bundle of cables.

I understand this is not a big problem for most, but it makes it not practical for my case.

 

[Kmpkt]

Figure the connectors would run into the DIMMs on your build?

 

[Hahutzy]

Possibly, but there's more chance that the connectors in the middle will hit the bottom of the middleboard and/or the motherboard.