Dual 12V Rail PSU Shoot Out

Today, we're going to take a look at three different power supplies.  The power supplies are from three different manufacturers: Enermax, Antec and Silverstone.  All three are quiet different from the next in several ways, but all three have two 12V rails.

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

As you can see, these are very substantial power supplies and will likely work fine for 99% of our readers.  I wouldn't hesitate using any of these power supplies with an SLI system, even though none of them are actually certified by nVidia to do so.

First, let's take a look at the Enermax.....

The Enermax EG495P-VE

The Enermax power supply certainly looks "pretty," and without having to bling things out with a glossy finish and UV reactive cables. The housing is an understated metallic blue, with a presigeous "Enermax" stamped out into the steel.

Enermax finds a happy medium: Sleeve bearing fans are often quieter than ball bearing fans.
Enermax always uses ball bearing, which last longer, but Enermax has no issues with noise.

A little blast from the past:
My first "real" PSU was an Enermax.  It was in 2000 and I remember it being the first PSU I had ever owned that had a "grill" instead of having the fan vents cut into the steel.

The only real "added feature" to this unit is the speed controller for the fan.  At idle, there was little to no difference between the lowest setting and the highest setting.  In other words, the power supply was very quiet regardless of how it was set.  Since we are going to load the power supply up pretty high for a fairly long period of time, I'm going to leave the knob cranked all of the way up.

The knob on the back, shown here, adjusts the fan's speed.

All of the cables have webbing on them coming out of the power supply....

But only that ATX connector is webbed all of the way to the end.

I jumped on the "heatsinks too small" bandwagon and I think I'm going to jump back off.
If heatsinks are too small, they don't disipate heat from the MOSFET's effectively.  Too large and they block air-flow.  I think I'll leave the "heatsinks are too small" judgement calls to the engineers.

Let's look at the Antec NeoPower next.....

The Silverstone Zeus ST52F

The Silverstone is more of a "black chrome" finish than the "titanium" we're used to seeing.  Refreshing, actually.

The Silverstone unit looks sharp and comes with more, and more different, connectors than any of our other power supplies.  At an average price of $109-$129, the Silverstone is the most expensive unit of the three reviewed today.

A fist full of connectors.

There's no shortage of connectors, either.  With a PCI Express connector, 6-pin Aux, 8-pin AUX and four SATA connectors, there should be plenty of connectors for your rig.

The Silverstone features a less commonlt used 2x3 AUX connector.  Here it's shown next to the PCI Express power connector.

To obtain a 2x2 power connector, one must adapt the 2x4 connector with the above adapter (bottom of two shown.)  The connector at the top of the photo is an adapter included with the power supply because the wrong connector was put on the end of the PCI Express connector.  A small note was included with the power supply explaining the error.

The two 80MM fans that cool the Silverstone are quiet, but not as quiet as Enermax's and not as quiet as Antec's 120MM fan.

Inside the power supply, we find a lot of good quality components and construction.  Most notable is the perforated copper heatsink. The Silverstone also features Actvice Power Factor Correction circuity.

Let's take inventory of the cables included with each power supply...

A look at the cables...

*Two of the 5.25" power connectors are included in a Ziploc bag and need to be "crimped" onto the cable.
** The two additional 3.25" connectors come in the form of a Y-adapter that fits onto a 5.25" power connector.
*** Two SATA connectors are included in a Ziploc bag and need to be "crimped" onto a cable.
# This AUX connector is a 2x3 interface instead of the typical row of 6 found on most boards.

The Enermax 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 Antec and Silverstone come as 24-pin connectors and include a 24-to-20 pin adapter.

The Antec actually comes with additional 5.25" drive Molexes and SATA connectors that crimp onto other power wires.  This allows the user to crimp on their own connectors whereever they may need them.  The NeoPower is also the only power supply we reviewed that had a Fan Only power connector that controls case fan RPM by lower voltages during lower temperatures.

Now that we've covered the obvious attributes of each power supply, let's load 'em up and see who squirms!

Load test results:

	Enermax EG495P-VE
	Total Wattage	12V1	12V2	5V	PF	Efficiency
Test 1	367W	12.16	12.07	5.06	.69	80%
Test 2	462W	12.08	11.96	5.06	.70	78%
Test 3	438W	11.97	11.93	5.07	.70	78%
Test 4	437W	12.10	11.95	5.06	.70	78%
Test 5	508W	12.02	11.90	5.06	.70	76%
5VSB Only Load					.56	46%

Stable rails and awesome efficiency really made the Enermax shine. 

The Antec NeoPower exhibited the most fluctuation on the 5V rail, but the least fluctuation on the 12V rail. Throughout all tests, the 12V rail never fluctuated more than .04V.  It also had Power Factor Correction that held up even during the +5VSB test.

Even though it's rated at 520W, the Silverstone had the lowest rated 12V rails (all of it's rated power is on the 5V rail.)  The 12V rail moved around quite a bit.  Furthermore, the 12V rail actually bounced around while it was under a steady load.  It was actually difficult to get a reading because voltage would bounce by about .2V every other second.

So where does that put us?

In Conclusion...

No doubt that all three of these power supplies are awesome, but despite the pros, there's still some cons...

Enermax EG495P-VE

Pros:

• At just under $100, the least expensive of our three PSU's
• Highest rated 12V rails of the bunch.
• Very stable rails.
• Very quiet, even with fans turned up to full RPM's.
• Very efficient.

Cons:

• Lacks in the bling department (modular, lights, etc.), but that doesn't matter to most users.
• No Active PFC.

Antec NeoPower

Pros:

• Modular cables.
• Extremely stable 12V rails.
• Very quiet.
• Fan only connector controls case fans.
• More connectors than you could possibly ever need.

Cons:

• Definitely the least prettiest modular power supply I've seen.

Silverstone Zeus ST52F

Pros:

• Fairly quiet.

Cons:

• Expensive.
• Rails were not very stable.
• Expensive.

Grading these was tough, but with stable rails and quiet operation, both the Enermax and Antec are going to come out on top.  The Enermax having better efficiency weighed out the Antec's PFC, but the Antec being modular bumped the Enermax.  That said, don't hesitate to consider the Enermax if modular cables are unimportant to you.

Enermax EG495P-VE scores a very high 9.

Antec NeoPower 480W scores a 9.5.

Slightly louder than the other two, and with not so stable rails, the Silverstone gets knocked down a few notches.  The price hurts it's score too.  Still, the Silverstone is a very good power supply overall, but in this shootout it's a bit out done.

Silverstone Zeus ST52F scores a high 8.