Recommend PSU with high efficiency at lower power demands

boxmonkey · Post by **boxmonkey** » Thu Oct 12, 2006 9:35 pm

I have a rig that is presumably capable of creating a fair amount of demand for power at times (though I have not tested it), but which spends the vast majority of its time idling. With my current PSU it spends most of the day using 180-200W.

I would like a PSU that can provide high efficiency at the lower end of the power usage scale while still giving some headroom. I'm not sure exactly how much headroom, but my 5 year old 420W Cheiftec seems to do just fine. I'd imagine 380-400W is a good range, but I'll let you decide when you see the specs. I would love a modular PSU as well for better cable management, but those only seem to come on the higher power scale whic his then less efficient at the lower part of the scale. I really don't care how efficient the PSU is at 300-400W because it will spend only 1-2% of its operating time there.

Here's the rig:
Dual Athlon MP 1800+
1 10kRPM SCSI drive
2 7200RPM IDE drives
1 CDRW (Lite-On)
1 DVDRW (generic)
All kinds of USB stuff attached
5 80mm fans
Matrox G450 Dual Head card
Adaptec 29160 SCSI card
Wireless G PCI Card
Turtle Beach Santa Cruz

This system is getting old but it's still blazingly fast for most applications. I would like something that could handle future upgrades, maybe building a new PC in a year or two...if not then at least upgrading the video card to something a bit more modern (which probably means more power hungry

)

Any recommendations would be greatly appreciated. Pointers to where I can find them in the US would be doubly appreciated.

Thanks!

Post by **NeilBlanchard** » Fri Oct 13, 2006 2:22 am

Greetings & welcome to SPCR!

The SeaSonic S12 380 or 430, or the Energy Plus version are probably the most efficiency at this level:

http://www.silentpcreview.com/article226-page1.html
http://www.silentpcreview.com/article656-page1.html

http://www.silentpcreview.com/article28-page6.html

The SeaSonics sold at NewEgg

boxmonkey · Post by **boxmonkey** » Fri Oct 13, 2006 12:57 pm

Newegg doesn't seem to have the HE versions of the 380 or 430. Do you know of anywhere else that sells SeaSonic in the US?

jaganath · Post by **jaganath** » Fri Oct 13, 2006 1:04 pm

boxmonkey wrote:Newegg doesn't seem to have the HE versions of the 380 or 430. Do you know of anywhere else that sells SeaSonic in the US?

There are no "HE" versions of the S12-380/430; they are pretty much the most efficient PSU for your power draw range.

dhanson865 · Post by **dhanson865** » Fri Oct 13, 2006 7:49 pm

I've never bought from saveateagle before but I've dealt with casemod, zipzoomfly, and newegg before.

I also have no idea if the pricing for the any of these items is stable. Sales, clearance, out of stock, could be points to consider on the lower wattage and older items including the S12-500. The M12-500 and S12-550 are extremely new and the price could drop or rise. Finally I didn't do the most exaustive search in the world. I just used the SPCR pricegrabber and froogle and compared those to newegg.

ZipZoomFly seems to have the best deal on the S12-380 right now around $7x shipped to my zip. Unfortunately this is the model with the least hard data on SPCR.

case-mod.com seems to have an ok deal on the S12-430 right now around $8x shipped to my zip.

case-mod.com seems to have an ok deal on the S12-500 right now around $11x shipped to my zip.

saveateagle.com seems to have an ok deal on the S12-550 right now around $14x shipped to my zip. Casemod has it for a few bucks more.

case-mod.com seems to have an ok deal on the M12-500 right now around $14x shipped to my zip.

If futureproofing and modularity is the idea the M12-500 is the only modular seasonic. Unfortunately we don't have sound data for that model yet. The only SPCR review for the M12 series covered the M12-700 but it is likely the M12-500 is similar in noise to the S12-550 at loads below 200W.

The S12-550 is about the same cost and has better noise and power usage/efficiency numbers. It's also the absolute quietest at idle power levels though with your system that shouldn't matter.

This is the table I'm looking to finish off.

Code: Select all

Model       Output (W)  40      65      90      150     200     250     300     400     500     600
        Efficiency
0 PCIe
     400HT-80+*****     76.6%   81.5%   82.8%   85.3%   85.3%   84.3%   83.9%   82.6%
0/1 PCIe (sleeved versions have 1, non sleeved US have 0, some international non sleeved had 1)
     S12-330            68.1%   75.5%   77.9%   80.3%   82.0%   80.9%   79.9%   **
     S12-380              .?%     .?%     .?%     .?%     .?%     .?%     .?%   ****
     S12-430              .?%   78.3%   80.5%   81.6%   81.8%   80.5%   79.6%   *
2 PCIe
     S12-500/600          .?%   75.1%   78.0%   81.2%   82.0%   81.8%   81.1%   79.0%   79.7%   78.9%
     M12-500              .?%     .?%     .?%     .?%     .?%     .?%     .?%     .?%     .?%
     S12-550E+          68.8%   74.7%   78.6%   81.9%   84.8%   84.3%   84.1%   82.9%   81.2%   ***

         Temp Rise (Â°C)
400HT-80+*****           1       2       2       2       3       4       5       5
S12-330                  3       4       2       3       7       8       6       **
S12-380                  ?       ?       ?       ?       ?       ?       ?       ?
S12-430                  *       3       4       5       5       7       8       *
S12-500/600              ?       2       1       3       3       3       5       5       6      7
M12-500                  ?       ?       ?       ?       ?       ?       ?       ?       ?
S12-550E+                2       2       3       5       8      12      10      12      13      ***

         Noise (dBA@1m)
400HT-80+*****          22      22      22      22      23      30      36      38
S12-330                 21      21      21      21      22      30      35      **
S12-380                  ?       ?       ?       ?       ?       ?       ?       ?
S12-430                  *      20      20      22      25      29      32      *
S12-500/600              ?      21      21      22      25      28      34      39      40      40
M12-500                  ?       ?       ?       ?       ?       ?       ?       ?       ?
S12-550E+               20      20      20      20      20      21      25      36      43      ***

* S12-430 was not measured at 40W or 400W. Ambient conditions during testing were 21Â°C and 19 dBA SPL. At 430W it got 75.5% efficiency at 37dBA and a rise of 8Â°C. 

** S12-330 was also measured at 330W. Ambient conditions during testing were 21Â°C and 20 dBA, 122V/60Hz. It got 78.3% efficiency at 37dBA and a rise of 8Â°C.

*** The S12-550E+ was also tested at 550W.  Ambient conditions during testing were 22Â°C and 17 dBA. It got 79.7% efficiency at 40dBA and a rise of 14Â°C.

**** The S12-380w has never been tested by SPCR.

***** The 400HT-80+ Is not available at retail and lacks PCIe connectors and only has 2 SATA connectors. Below 250W the 400HT-80+ is noisier than the S12-330, S12-420, and S12-550E+. Presumably this is best used in a server where drives and/or other fans would hide the extra noise.

EsaT · Post by **EsaT** » Sat Oct 14, 2006 12:20 am

Now I wouldn't call idle power draw of that as low in any way.

About only part which doesn't consume so much (when compared to parts used in most PCs) is graphic card.

Have you checked how much it consumes under load?
That would be good starting point in estimating real consumption levels and then what kind head room would be needed.
(I would expect PSU to have sub 75% efficiency even at peak)

One thing worth of checking is from what voltage motherboard draws power for CPUs.

boxmonkey · Post by **boxmonkey** » Sun Oct 15, 2006 11:02 am

Thanks. The recommendation to see what power consumption is like under full load is a good one. I will hook up my computer to my kill-a-watt again and run it under full load to see what happens to the power usage.

Unfortunately I have no way of measuring how much power the motherboard and CPUs are using separately.

Engineer · Post by **Engineer** » Sun Oct 15, 2006 3:56 pm

Based on SPCR's review and my own personal experience, I would stay away from the S12 Energy Plus models. Mine has a high pitched whine/buzz until I load it up. I finally had to add a resistor circuit to the 12 volt rails to quieten it down. Now of course it burns more power than it really needs, but it is finally quiet. I'll be changing to a Kentsfield Quad Core in the future so I doubt I'll always need the resistor circuit (unless it whines in sleep mode).

drees · Post by **drees** » Sun Oct 15, 2006 4:24 pm

EsaT wrote:Now I wouldn't call idle power draw of that as low in any way.

Heh, no kidding, when I read the title I was expecting to hear about less than 75w for sure, not ~200w which is actually is pretty high in my experience.

Most PSUs are pretty efficient at the type of idle power that boxmonkey's machine is pulling.

boxmonkey · Post by **boxmonkey** » Wed Oct 18, 2006 4:19 pm

I finally got around to testing the power consumption at max load and...I couldn't.

This system is normally rock solid and I have run torture tests on it in the past with no problem (although my goal has never been to maximize power draw), but this time I could not get over 350W without crashing. I don't know if it's an overheating problem or if my current "450W" PSU is crapping out at around 350W.

What I was trying to do to test max draw:
Run distributed.net client (2 threads) to keep CPU usage pegged at 100%
Defrag 10k RPM SCSI drive.
Burn a CD with DVDRW.
Surf the web using wireless card.
Charge cell phone with USB port.

Anyway, we know it can pull at least 350W although it takes a lot to get it there, so I should probably be looking at the 430 or 500W just to be safe.

I guess my idle power draw is high, I guess I was thinking low for power consumption, not low for idling. When the drives spin down my idle draw drops to 180, and I was hoping that with an efficient PSU that would drop more. I just wish they could optimize efficiency for the "low" end of the power spectrum and not worry about efficiency so much at the high end, since that's where most personal computers spend most of their time.

drees · Post by **drees** » Wed Oct 18, 2006 6:51 pm

The point some of us are trying to make is that 180w at idle is in the sweet spot of PSU efficiency. It's not until you drop below 30% PSU capacity that it's harder to stay efficient.

dhanson865 · Post by **dhanson865** » Fri Oct 20, 2006 12:42 pm

drees wrote:The point some of us are trying to make is that 180w at idle is in the sweet spot of PSU efficiency. It's not until you drop below 30% PSU capacity that it's harder to stay efficient.

That depends where/how he measures. If he is measuring at the wall with an old PS that gets 65% effieciency 180w AC becomes 117w DC. While >90w DC isn't very low it is well below the sweet spot for the new Energy+ models from Seasonic which don't get super effecient until you break the high side of 200w DC.

Now if he is idling at 180w DC that is high but since he doesn't say what his old PS is and he doesn't mention how he is testing shouldn't we assume the worst. He likely has a non PFC or passive PFC, low effeciency stock PS (especially considering it doesn't even handle the advertised wattage in his tests).

It'd be a lot easier to quantify this and make a serious recommendation if we knew:

1. the old power supply make, model, revision, date of manufacture
2. the method of testing power draw
3. the equipment used in said method

Considering his PS couldn't deliver the advertised/rated wattage he and possibly others might want to revisit the blue/green sidebar on page three of the classic article http://www.silentpcreview.com/article28-page3.html

Of couse I'd add one word to the title of that sidebar:

POWER SHMOWER or How Cheap PSU Power Ratings Mean Almost Nothing

EsaT · Post by **EsaT** » Fri Oct 20, 2006 10:50 pm

dhanson865 wrote:Now if he is idling at 180w DC that is high but since he doesn't say what his old PS is and he doesn't mention how he is testing shouldn't we assume the worst. He likely has a non PFC or passive PFC...

Reactive power isn't present in watts, for apparent power unit is VA. Also that second CPU is definitely increases idle power draw.

Of couse I'd add one word to the title of that sidebar:

POWER SHMOWER or How Cheap PSU Power Ratings Mean Almost Nothing

Q-Tec category is missing there!

Or how about this "500W" PSU: peak from 3.3V&5V is 180W, peak from 12V is 192W so even those doesn't add up to 500W!
(if you do the math rated power is ~300W and I wouldn't count even to that)

In newer models they have been satisfied to just giving peak values
http://download.qtec.info/downloads/qtecMM/14348.tif

dhanson865 · Post by **dhanson865** » Sat Oct 21, 2006 6:23 pm

Pricing update

3gplaza.com has the S12-380 right now around $6x shipped to my zip. ZipZoomFly.com is a close second at about $5 more putting it at $7xUnfortunately this is the model with the least hard data on SPCR.

3gplaza.com has the S12-430 right now around $8x shipped to my zip. case-mod raised the price in the last few days but they and tons of others will sell it in the $9x or above range.

3gplaza.com has the S12-500 for $11x to my zip. ZipZoomFly.com has the S12-500 right now $120 with free shipping Personally I wouldn't buy this power supply unless it got into the $9x range. It just doesn't compete well between the old 430 and the two new lines.

case-mod.com has the S12-550 right now around $15x shipped to my zip. I'd be jumping on this if it were around $12x.

case-mod.com has the M12-500 right now around $14x shipped to my zip. For the orginal poster in this thread this might be the ideal power supply. I'd only be looking at it seriously if it was more than $20 less than the S12-550 and no more than $20 above the price of the S12-430.

Of course if they'd make a S12-Energy+ 450 that could slide into the price slot between the S12 Energy+ 550 and the old S12-430 I'd be looking at that for sure. What the heck, let me toss in my thoughts on that subject in the next reply

dhanson865 · Post by **dhanson865** » Sat Oct 21, 2006 7:09 pm

So the Corsair HX520W and price changes with the S12-550E+ have made that post a little dated...

dhanson865 · Post by **dhanson865** » Mon Feb 12, 2007 6:36 pm

The obvious choices right now are S12-380 for cost and efficiency below 100 watts, the S12-550E+ for lowest noise below 200 watts and best efficiency in the mid range, or the Corsair HX520W for lower noise and better efficiency above 250 watts.

It's a good lineup. The only thing that would make it better is if they made a S12Energy+ 450

Code: Select all

Model       Output (W)  40      65      90      150     200     250     300     400     500
        Efficiency
1 PCIe
     S12-430              .?%   78.3%   80.5%   81.6%   81.8%   80.5%   79.6%   *
2 PCIe
     HX520W             67.7%   72.5%   77.1%   81.0%   84.5%   85.2%   85.1%   83.7%   81.3%
     S12-550E+          68.8%   74.7%   78.6%   81.9%   84.8%   84.3%   84.1%   82.9%   81.2%

         Noise (dBA@1m)
S12-430                  *      20      20      22      25      29      32      *
HX520W                  22      22      22      22      22      22      22      29      43
S12-550E+               20      20      20      20      20      21      25      36      43

* S12-430 was not measured at 40W or 400W. It was tested at 430W.

As you can see on the tables above the Energy Plus/Corsair models have a huge advantage in noise and efficiency over the regular S12 models when you get above 150W. You should also be able to notice that the S12-430 has a large advantage in efficiency below 150W.

So if you want the ability to get above 90W and not have the fan ramp up and also want the better efficiency of the S12-430 when you are idling in the 45 to 90 watt range there isn't a best of both worlds choice currently.

What I'd like to see is a S12-450 Energy Plus model.

Give me 130W to 150W on the 3.3v + 5V spec if it lowers cost. I'm more concerned about +12v rails.
Give me 30A or more on the +12V rails.
Give me the same fan and fan controller as seen in the S12Energy+ 550.

Most importantly I'd like to see the new power supply beat the S12-430, HX520W, and S12-550E+ in efficiency in the 40W to 200W range and keep the noise profile of the S12-550E+.

The 80 PLUSÂ® performance specification requires power supplies in computers to be 80% or greater energy efficient at 20%, 50% and

100% of rated load. The goals* are:

>70% at 40W
>79% at 65W
>82% at 90W
>83% at 150W
>85% at 200W
>84% at 250W
>82% at 300W
>82% at 400W
>81% at 450W

*all at the strict testing standards of SPCR on 120v AC. Presumably the marketing claim would be 88% peak efficiency under ideal conditions (low ambient temp on 240v AC).

dhanson865 · Post by **dhanson865** » Mon Feb 12, 2007 7:56 pm

OK, the pricing recap:

S12-380 under $70 shipped from case-mod.com with sleeved cables and a PCIe connector. Pretty much the same price at http://www.xpcgear.com/s12380.html if case-mod goes up on price.

S12-550E+ around $125 shipped from ewiz.com

Corsair HX520W $100 shipped from buy.com, with securemart, and zipzoomfly as alternate sources.

I'm actually quite surprised that the HX520W is so cheap as it has the flattest fan noise curve and has modular cables.

drees · Post by **drees** » Tue Feb 13, 2007 10:48 am

I'm surprised that no one has mentioned the Antec EarthWatts or NEO HE series. The EarthWatts are 80plus rated and the NEO HEs are also very efficient, very similar to the Seasonics. You can find both at NewEgg.

The EarthWatts model comes in 380, 430 and 500w models. The NEO HE also comes in a wide variety of models.

kaange · Post by **kaange** » Tue Feb 13, 2007 3:12 pm

One thing to keep in mind is that efficiency is a percentage thing so at a low power draw, the difference in the PSU power consumption between a low efficiency and high efficiency (at that low level) PSU will be only a few watts rather than a substantial difference.

Basically, the system draw would swamp any PSU consumption difference.

Howard · Post by **Howard** » Tue Feb 13, 2007 4:08 pm

http://www.case-mod.com/seasonic-s12380 ... tml?src=fr

dhanson865 · Post by **dhanson865** » Tue Feb 13, 2007 5:49 pm

drees wrote:I'm surprised that no one has mentioned the Antec EarthWatts or NEO HE series. The EarthWatts are 80plus rated and the NEO HEs are also very efficient, very similar to the Seasonics. You can find both at NewEgg.

The EarthWatts model comes in 380, 430 and 500w models. The NEO HE also comes in a wide variety of models.

The EarthWatts is almost always noisier than a S12 and is ALWAYS noisier than the Corsair. That just doesn't appeal to me.

The Antec Neo HE ramps up too quickly and is noisier still. It also never breaks 80% efficiency at any wattage.

Code: Select all

Model       Output (W)  40      65      90      150     200     250     300     400     500     600
        Efficiency
Antec Neo HE 430        67.3%   75.5%   76.2%   79.0%   77.8%   77.2%   75.9%   72.0%
Earth Watts 430         70.8%   75.6%   78.3%   81.0%   83.5%   83.2%   82.4%
     S12-430              .?%   78.3%   80.5%   81.6%   81.8%   80.5%   79.6%
     HX520W             67.7%   72.5%   77.1%   81.0%   84.5%   85.2%   85.1%   83.7%   81.3%

         Noise (dBA@1m)
Antec Neo HE 430        20      20      20      21      26      31      37      40
Earth Watts 430         22      22      22      22      24      29      37      43
   S12-430               *      20      20      22      25      29      32      37
HX520W                  22      22      22      22      22      22      22      29      43

There are good reasons why those two are rated lower than the S12 series, the Corsairs, and the S12-Energy+ models on the recommended list.

http://www.silentpcreview.com/article699-page1.html

drees · Post by **drees** » Tue Feb 13, 2007 6:11 pm

At the power output the original posted will be running at (150-250w) the EarthWatts 430 and Seasonic S12-430 are virtually identical in efficiency and noise level. The EA-430 doesn't get noisier than the S12-430 until over 300w using the data you posted yourself.

It's generally cheaper and easier to find as well which is why I recommended it. The Neo HE is generally slightly less efficient, but not much.

I'm still surprised that the normal S12-430 isn't 80plus certified given it's nearly identical performance to the EA-430.

dhanson865 · Post by **dhanson865** » Tue Feb 13, 2007 7:32 pm

I'm surprised the Earthwatts got 80Plus certified when it can't beat 80% at 90watts in real world testing.

Myself I'm paying much more attention to the under 100w range than the original poster in this thread. So sue me if I try to take a specific thread with a good title and make it more general purpose.

I'm simply taking this opportunity to think out loud. You are more than welcome to try to convince me that I'm wrong. The numbers I'm quoting are from SPCR reviews. Feel free to use them against me.

A month ago I would have said get the S12-380 hands down don't even waste the time or money thinking about the 430 or any other brand/model. Now I'm looking at the Corsair at or below the $100 mark as a very tempting deal.

drees · Post by **drees** » Wed Feb 14, 2007 1:19 am

I don't know if you can call SPCRs testing "real world" even though it attempts to simulate it.

You can read the 80plus test results for the EA-430 here:
http://www.80plus.org/manu/psu/document ... Report.pdf

Seasonic has 27 PSUs which have been 80plus certified, but the S12 series isn't listed at all on the 80plus website.

http://www.80plus.org/manu/psu/seasonic.htm

The 80plus test results tend to be a percent or two higher than SPCRs test results.

dhanson865 · Post by **dhanson865** » Wed Mar 14, 2007 8:28 pm

drees wrote: Seasonic has 27 PSUs which have been 80plus certified, but the S12 series isn't listed at all on the 80plus website.

http://www.80plus.org/manu/psu/seasonic.htm

Sorry, you seem to be lost in the model numbers:

SS-500ES is the M12-500
SS-500HT is the S12-500
SS-550HT is the S12-550 Energy+
SS-600HM is the M12-600
SS-650HT is the S12-650 Energy+
SS-700HM is the M12-700

So Seasonic has 6 retail products with 80plus certs and if the S12 Energy+ models and M12 models made it the Corsair equivalents should be listed even though they apparently aren't 80plus certified. As to the rest I'm just not ready to spend the time decoding model numbers all night long...

dhanson865 · Post by **dhanson865** » Wed Mar 14, 2007 8:53 pm

whoa, Buy.com has the hx520w for $89.99 shipped after $10 mail in rebate. Even if you ignore the rebate it's $100 shipped (free shipping). Rebate is only good for two more weeks.

I do also see that the Earthwatts series are abundant like you said. Apparently even CompUSA and other brick and mortar types carry them. While they don't have any sex appeal to them the 430 watt version can be found online for less than a S12 if every last cent matters to you and you have a system that idles at greater than 90 watts but never breaks the 200 watt barrier when it is under load.

I still like the S12-380 for systems that idle below 75 watts and will never break the 150 watt barrier and the Corsair HX520w for systems that will idle above 100 watts and will break the 200 watt barrier.

I suppose if the S12 Energy+ 550 were to ever be less expensive than the Corsair HX520W it would make a fine substitute but under the current pricing I find it hard to want to pay for a M12 or a S12 Energy+ with so many other cheaper choices out there.

So that makes the short list:

Code: Select all

       S12-380 $60 + S&H
Earthwatts 430 $50 + S&H
Corsair HX520W $90 shipped

With a nod to the S12 for low power systems even though it is slightly more expensive.

jojo4u · Post by **jojo4u** » Thu Mar 15, 2007 4:14 pm

boxmonkey wrote: Here's the rig:
Dual Athlon MP 1800+
1 10kRPM SCSI drive
2 7200RPM IDE drives
1 CDRW (Lite-On)
1 DVDRW (generic)
All kinds of USB stuff attached
5 80mm fans
Matrox G450 Dual Head card
Adaptec 29160 SCSI card
Wireless G PCI Card

1st have a look at disconnect.

2nd I'd be concerned about the 5 V requirements since ATX specs puts emphasis on 12 V since some years. You Athlons could suck like crazy on the 5 V line. What power connectors does you board supply?

dhanson865 · Post by **dhanson865** » Sat Jul 21, 2007 11:59 am

I still don't see the appeal of the Neo HE but with pricing changes an Earthwatts on sale looks more appealing.

Code: Select all

[code]
Model       Output (W)  65      90      150     300
        Efficiency
     S12-330            75.5%   77.9%   80.3%   79.9%
     S12-380              .?%     .?%     .?%
Antec Neo HE 430        75.5%   76.2%   79.0%   75.9%
Earth Watts 430         75.6%   78.3%   81.0%   82.4%
     S12-430            78.3%   80.5%   81.6%   79.6%
     HX520W             72.5%   77.1%   81.0%   85.1%
     S12-550E+          74.7%   78.6%   81.9%   84.1%

         Noise (dBA@1m)
S12-330                 21      21      21      35
S12-380                  ?       ?       ?
Antec Neo HE 430        20      20      21      37
Earth Watts 430         22      22      22      37
S12-430                 20      20      22      32
HX520W                  22      22      22      22
S12-550E+               20      20      20      25

[/code]

oh and here is some trivia for your reading pleasure

Fan Voltage at idle Brand/Model
4.5 Seasonic S12 rev 1
4.3 Seasonic S12 rev 2 (note this is the sleeved version not the roman numeral II version that is newer)
4.2 Antec Earth Watts
4.1 Antec Neo HE
3.9 Seasonic M12
3.84 Corsair HX
3.8 Seasonic E+ and the old 500/600 watt S12

truckman · Post by **truckman** » Sat Jul 21, 2007 4:10 pm

drees wrote:I'm still surprised that the normal S12-430 isn't 80plus certified given it's nearly identical performance to the EA-430.

I just noticed that Newegg has recently started carrying 80plus versions of the S12-380 and S12-430.

Recommend PSU with high efficiency at lower power demands

Recommend PSU with high efficiency at lower power demands

Pricing update

Re: Recommend PSU with high efficiency at lower power demand