Introduction:

It's that time again.  I've got three more power supplies with dual 12V rails and a power supply tester waiting to test them.

I changed some of my loads from the last review.  I didn't blow anything up, so I figured I'd

Test 1:  .I've got +12V1 and +12V2 at 12A.  I figured this was a good "base" test.

Test 2:  The +12V1 and +12V2 are juiced up to 14A to emulate a higher than average load.  This may be above spec for some power supplies.

Test 3:  This test throws the power supply a bit off balance   +12V1 goes up to 16A, while +12V2 goes back down to 12A.  The 5V is brought up to 16A

Test 4:  This test is the opposite of three.  +12V2 is now at 16A and +12V1 at 12A.  The 5V is still at 16A.

Test 5:  This test is rather balls to the wall.  The 5V is brought down to 14A, but both 12V rails are whacked with a 16A load.  This is a 32A, or 384W, on the 12V combined rail.  This is out of spec for most power supplies, but I find many can handle this I then move the rails up to a combined wattage of 408W.  This can be done by putting 17A on each rail or 16A and 18A... depending on how the power supply is spec'd.

The only exception I made for this test is the Seasonic.  Since the Seasonic was only a 430W power supply (I take what I can get) the 12V load was so out of spec the overload protection immediately kicked when I applied it.  For the fifth and final test, the Seasonic gets a 14A load on 12V1, a 15A load on 12V2, a 14A load on the 5V rail and a 10A load on the 3.3V.

What is a 12V rail and why are there two of them?

I suppose we should break down what we're talking about here....   The rails (named after steel rails that carried power to electric trains) are what each different colored wire (yellow for +12V, red for +5V, etc.) derive it's power from.  With the demand on +12V becoming greater and greater, Intel decided it would be "safer" to split the duty of supplying +12V across two rails.  It's "safer" because inexpensive transistors capable of supplying more amperage (say more than 34A) at any kind of decent efficiency (70% or better) are subject to blowing up.  :-)  That's not very safe.  ;-)

To split the duty up between two +12V rails, one can use cooler running, cheaper transistors to supply the power.  Furthermore, this isolates devices on one rail from another, so EMI introduced by lighting inverters and drive motors can be isolated from sensitive components like the CPU and video card.

(14 * 12) + (16 * 12) = 336?  What is this?  NEW math?

You'll often find that the capabilities of the +12V rails combined almost never equal what is listed for each rail individually added together.  This is because, although the two +12V rails are on separate transistors, they're still being fed by the same, single transformer and rectifier.  So one rail might be able to pull off 168W if loaded up by itself, and the other might be able to pull off 192W if loaded up by itself, but the amount of juice that can even get to those transistors (safely) isn't more than 336W, so you simply CAN NOT fully load both rails to their maximum capabilities.  And when I say "can not" load them, I mean load them without overloading them and staying within the tolerance of the rated rail.  I mean, I put 16A loads on 14A rails all day long... that doesn't mean it's recommended.  ;)

So back to the testing!

So we have our 5 tests, and we also have a +5VSB test that looks at the power factor and efficiency of a power supply when it's idle.  Power factor and efficiency will also be measured under all loads.  All loads are run for 15 minutes prior to deriving a reading and are run for 30 minutes before determining a pass/fail.  The usual stuff.

Noise will not be measured on a technical level.  As before, I will just give a "judgment" on how loud a power supply is.  If it can drown out my 2 1/2 year old dancing around to the Wiggles in the other room, it's loud.

Now, on to our testing....

Another Dual 12V Rail PSU Shoot Out

Today, we're going to take a look at three more power supplies with dual 12V rails.  The power supplies are from three different manufacturers: AMS Electronics, Seasonic Electronics and Thermatake.

Here are the voltages for each of our three power supplies:

AMS Mercury PP-4603
3.3V
5V
12V1
12V2
-12V
+5VSB
Maximum Output Current
24A
24A
18A
15A
1A
3A
Maximum Combined Peak Wattage
140W
360W
27W
460W

 

Seasonic S12
3.3V
5V
12V1
12V2
-12V
+5VSB
Maximum Output Current
30A
30A
14A
15A
0.8A
2A
Maximum Combined Peak Wattage
150W
348W
9.6W
10W
430W

 

Thermaltake TWV500
3.3V
5V
12V1
12V2
-12V
+5VSB
Maximum Output Current
30A
30A
18A
18A
0.5A
2A
Maximum Combined Peak Wattage
350W
216W
6W
10W
500W

Once again, we are dealing with some fairly substantial power supplies.  Each has it's own little market niche.  The AMS is rather "plain," but comes to us with a mere $60.  Yes, there are other 500W dual 12V rail power supplies out there for $60, but it's not often you find QUALITY for $60.

The Seasonic product line has always been touted for it's great efficiency and at, or just under, $100 is a bit more expensive than the AMS.  But with one 120MM fan instead of a pair of 80MM fans, it should be quieter.  Furthermore, with better efficiency it should run cooler; therefore the fan should not have to spin as fast.  However, this Seasonic makes no claim to be as efficient as models before it that have succeeded the "80 Plug Program" of having an 80% efficiency.  The label for the S-12 states it has "up to 80% efficiency."  Hmm... A bit suspicious if you ask me.  Even power supplies that state they have at least a 70% efficiency can often have 75% or better efficiency.

At $120, the Thermaltake TWV500 is the expensive power supply in this line up.  Certainly, judging by the label, the most powerful.  And with a blue LED coming out of it's 120MM fan and modular cables, is the one with the most bling.  We also pay a bit more for a "Total Watts Viewer" or "TWV."  The TWV guesstimates the wattage the power supply is putting out based on the amperage it measures on the rails.  This device also has a speed controller for the PSU's 120MM fan as well as the "bonus" 120MM fan included in the package.

First, let's take a look at the AMS Mercury....

The AMS Mercury PP-44603

Ahh!! Old school. In a land of bling and dookie, the AMS looks like... well... a power supply.  There's no fancy paint job, no lights, no windows.  No modular cables.  Just gunmetal gray and two 80MM fans.

When I first powered up the unit, the first thing that impressed me was how QUIET it was.  AMS's website claims 28dba or less.  I would say, "A LOT less."  Even under load, when the fans spun up to full RPM, I'd have to say the fans were still quieter than a lot of 120MM fans out there.

I'll tell you honestly, I never thought of AMS as someone to go to for an ATX power supply.  A redundant power supply, external drive array enclosure, rack cabinets, etc.  But the construction looks good, the numbers on the label certainly look good... heck!  At $60 the price was right too.

The cables were no frills.  Above we see the ATX 24-pin, a Xeon 8-pin and a 6-pin AUX (NOT a PCI-e.)  Apparently, there is another version of this power supply available with an ATX12V 2x2 connector and PCI Express.  I bought mine from Newegg.  They do NOT list which PSU comes with which cables. When you look at them on Newegg's website, the only difference is one has a "-X" after the part number and costs $5 less than the other.  This model isn't the one I bought.  I was later told that the model that was $5 cheaper that actually had the PCI Express power connector.

In order to use this PSU with an ATX12V, you have to adapt the 8-pin Xeon down to a 4-pin.  There's no such adapter included.  There is a 24-to-20-pin adapter that comes with an adjacent 8-to-4-pin adapter

The cables are all twisted really tight before the ends are put on.  This might help with EMI, but it made the cables stiff.  Handling them was like handling a live snake.  I'd best the cable one way and then with a snap the cable would squiggle in the other direction.

A pair of SATA power connectors are included with this power supply.

Inside the power supply we don't see anything too unusual.  The heatsinks are unique, smaller length than other power supplies, but substantially thicker and of a good width.

The caps on the AC side are "only" 1000uF.  This is the minimum I'd like to see.  They still seem to suit the AMS power supply just fine, but only long term use under high heat can really say for sure.

Now let's take a look at the Seasonic S-12 430W.....

The Seasonc S-12-430

The Seasonic unit we're taking a look at today is the entry level 430W from their newest S12 product line. 

Like all of the S12's, this one features dual 12V rails, a thermally controlled 120MM fan and a flat black finish.

The Seasonic features a very nice "honeycomb" vent along the back of the unit.  100~240V is supported through auto-switching.  Like most Seasonic's, our 430W has active power factor correction.

There aren't many frills with the Seasonic's cables.  They are twisted to help reduce EMI but none of the cables are covered.

The S12 comes with some plastic wire covers that one can use to "pretty up" their cable job...

After covering up my ATX and 2x2 connectors with the plastic, I decided I'd probably be better off without it.  It didn't look too hot and it made the cables very stiff and difficult to route.

Looking inside of the Seasonic, we can see no lack of quality.  The heatsinks are significantly larger than they need to be, the main transformer and choke coils shown at the above angle certainly convince me that overkill in construction is consistant throughout.

In the photograph of the other side of the inside of the power supply, we can see some fairly neat wiring.  You can also see the PCB for the fan thermistor precuriously leaning to the right.  This PCB is held to the main circuit board by only two points of solder.  Fortunately, you're not SUPPOSED to open your power supply, this shouldn't be an issue for anyone.

Now let's take a look at the Thermaltake TWV500.....

The Thermaltake TWV500

In the past, I've been pretty rough on Thermaltake, having blown up a couple of the 480W Butterflies and given them low scores.  A few other people around this mighty Internet have been disappointed with them as well, but some of these folks have been unfairly calling them "garbage."  I think this is a completely inaccurate assesment of their product. 

The problem with Thermaltake power supplies of the past have simply been the fact that they market a higher wattage power supply with all of it's power on the 5V rail in a market that NOW needs to have power on the 12V rail.  If you NEED a 480W power supply, you NEED more than 18A on your single 12V rail.  But the overall QUALITY of Thermaltake's power supplies have always been better than average.

Judging by the label on this particular unit, all previous animosity towards the Thermaltake power supply power supply line should be eliminated... IF the quality is still up to snuff too.

The side of the TWV500 looks very much like the other Thermaltake power supplies with a very large silver label facing out to your side panel's window.  The bling of this unit is quite subtle.  There's an LED in the fan, but it doesn't change colors.  It's always blue.  Also, there's no side window like one of the Thermaltakes I had reviewed in the past.

Above we can see the modular interface side of our power supply.  I love how clearly labeled the connectors are.  I mean; you can't really plug the wrong cable into the wrong port, but it's still nice.

We'll get to the actual cable count later, but I wanted to show you photos of the cables now.  They look very similar to the Antec Neo Power cables we reviewed last month.  Above are the drive Molexes and plenty of them.

Here's our two PCI Express cables and our 12V 2x2 connector.  The interface for the 2x2 connector is actually 2x4 so an SSI Xeon connector is a possibility, but no 8-pin power cable was included.  Perhaps one is sold separately.

Here's our main ATX connector.  I'm not sure why they bothered making this modular.  Unlike the Ultra X-Connect where the 20-pin can be exchanged for a 24-pin, this cable is a 24-pin natively that can have the last four pins taken off for backwards compatibility.  Making this cable modular does add a bit of resistance.  Not much, but under heavy loads the drop in voltage can be as much as .1V.

Above we have a photograph of the modular SATA cables...

Unlike most modular SATA cables, Thermaltake provides a separate 3.3V lead for future SATA drives that may start to use 3.3V.  Why make the connector separate?  So the interface on the power supply can still be used for regular PATA drive power connectors, of course.

Here's the other goodies we get with this power supply.  A 120MM fan and the TWV panel.  The fan is actually quite nice and the panel does give us the ability to adjust the speed of both the "bonus" fan and the fan in the power supply.  The only thing I don't like is the useless "total wattage viewer."  It's inaccurate and really quite useless.  Telling me how much juice is on EACH RAIL?  THAT would be cool.  Work on it Thermaltake!  ;-)

It looks like my useless "total wattage viewer" is really, really useless.  With a 468.8W load on the power supply, my TWV is reporting 10W.  I think I got a defective unit.  Oh well!  I'll RMA it later.  :-)

Inside we have gobs of caulk.  But the wiring is still fairly neat inside because of the use of a separate PCB for all of the modular cable interface.  This is similar to that used in Superflower manufacturered power supplies and gets rid of the mess of cables similar to that of the Ultra and Antec modular power supplies.

In the above two photos we can see the separate PCB's for the active power factor correction and thermistatically controlled fans.  We can also see the unique heatsinks used by Thermaltake.  The fins are slightly angled to help move the air from the fan to the vent at the back of the unit.

Now let's take a look at what cables we get with each power supply.....

A look at the cables...

  AMS Mercury PP-4603
Connectors
ATX
2x2 12V
PCI E
6-pin AUX
8-pin AUX
5.25"
3.5"
SATA
Fan Only
24
0
0*
1
1
7
2
2
0

*There is a "PCI-X ready" version of this PSU. Although this is not the unit I reviewed, apparently it has PCI Express connectors. I'm fairly positive a number of the other connectors are different as well.

  Seasonic S12
Connectors
ATX
2x2 12V
PCI E
6-pin AUX
8-pin AUX
5.25"
3.5"
SATA
Fan Only
24
1
0
0
1
6
2
2
0

  Thermaltake TWV500W
Connectors
ATX
2x2 12V
PCI E
6-pin AUX
8-pin AUX
5.25"
3.5"
SATA
Fan Only
20+4
1
2
0
0
9
2
4
0

The Thermaltake features a 20-pin ATX connector with a 4-pin connector that slides into the side of the ATX connector making it a 24-pin connector.  The AMS and Seasonic come with a native 24-pin connectors and include a 24-to-20 pin adapter.

The Thermaltake really takes advantage of it's modular features by providing way more cables than either the AMS or Seasonic and probably more than anyone would ever need.  Just plug in the cables you need and you're good to go. 

Unfortunately, the Seasonic lacks PCI Express connectors.  Adapters are available, and it's really doubtful that you would use this 430W for a PC with SLI, but it's really too bad it doesn't come with at least one.

Now that we've covered the cables, let's load up the power supplies and see what happens....

Load test results:
 
AMS Mercury PP-4603
 
Total Wattage
12V1
12V2
5V
PF
Efficiency
Test 1
405W
11.94
11.92
4.98
.71
74%
Test 2
450W
11.86
11.82
5.00
.72
72%
Test 3
460W
11.88
11.88
4.95
.72
71%
Test 4
460W
11.92
11.83
4.95
.72
71%
Test 5
516.8W
11.70
11.68
5.02
.74
68%
5VSB Only Load
.56
46%

For $60, this AMS is kicking ass and taking names.  The rails remained very consistant and I was able to put a load significantly greater than what the label showed.  Power factor and efficiency were average.

 
Seasonic S-12
 
Total Wattage
12V1
12V2
5V
PF
Efficiency
Test 1
407W
12.00
11.94
5.04
.99
76%
Test 2
453W
11.94
11.88
5.04
1.00
75%
Test 3
N/A
N/A
N/A
N/A
N/A
N/A
Test 4
463.4W
11.98
11.89
5.03
1.00
74%
14A/15A/14A/10A
465W
11.92
11.85
5.05
1.00
74%
5VSB Only Load
.91
45%

Surprisingly enough, the famed efficiency of the Seasonic, which no doubt is very efficient, is not even as good as the Enermax we reviewed last month.

Test 3 was a no go with the Seasonic.  The load was too much for the 12V1 rail.  The power supply didn't shutdown like it did when I applied the default Test 5 settings, but the voltages were fluctuating so radically, it wouldn't be fair to even attempt to document.

Certainly the Seasonic is a strong power supply.. for a 430W unit.  I can only imagine that the higher end models are just that much better.

 
Thermaltake TWV500W
 
Total Wattage
12V1
12V2
5V
PF
Efficiency
Test 1
411W
12.20
12.13
4.98
.98
72%
Test 2
459W
12.18
12.11
4.96
.98
71%
Test 3
469W
12.16
12.13
4.95
.98
71%
Test 4
469W
12.20
12.07
4.95
.98
71%
Test 5
530W
12.14
12.06
4.93
.99
69%
18A/18A/10A/10A
535W
12.16
12.06
4.95
.99
69%
5VSB Only Load
.94
25%

The Thermaltake has decent power factor and average efficiency (almost below average,) but it can certainly produce it's advertised power and then some.  During Test 5, the power supply didn't even flinch for the full half an hour it was loaded up.  I decided to take things further and loaded both 12V rails up to 18A to produce a total wattage of 535W.  Although efficiency dipped below 70%, it still stayed cool and the rails hardly fluctuated at all.  WOW!

So where does that put us?

In Conclusion...

AMS Mercury PP-4603

Pros:

Cons:

Seasonic S12

Pros:

Cons:

Thermaltake TWV500

Pros:

Cons:

I think we can see that the three of these power supplies really don't shoot-out each other.  If you want "cheap," the AMS.  If you want quiet, the Seasonic.  If you want modular, the Thermaltake.  If anything, we should take what we reviewed last month into consideration when grading these units.

The AMS really surprised me.  It was very inexpensive, yet put out a lot of stable power.  The efficiency was actually pretty good considering the price.  The only thing it lacks is Active PFC.

That said, the AMS Mercury gets a solid 9.

Last month, the Enermax EG495P-VE scored a "very high 9."  The Seasonic was just as efficient and noticeably quieter.  The Enermax has more power for only a little more money.  The Seasonic has active PFC. 

All and all, I think the Seasonic deserves the same score.  A very high 9.

If the S-12 was efficient as some of the power supplies that have made Seasonic famous, it'd get a 9.5 easily.

Thermaltake finally gets on my good side with their TWV500.  It's properly spec'ed out.  Does what it says it does and has a decent modular cable system.  Sure, the cables aren't the prettiest.  But they're still nicer than most non-modular cables.  It was also quiet, if you're willing to occupy your 5 1/4 bay with the fan controller. 

Thermaltake ALSO earns a 9.  Although, consider it a low 9 due to the poor efficiency.

I'm going to have to find some crappy power supplies to review.  I'm not feeling too comfortable with all of these warm fuzzy nines everywhere.....



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