Ultra brief PSU comparo: OCZ vs. Cooler Master vs. Enermax

Edward Ng · Post by **Edward Ng** » Fri Oct 15, 2004 11:41 pm

This evening, I happen to have three power supply units on me that prove to be interesting in one way or another. Although I do realize that it's difficult to compare these three directly, due to different wattage ratings, fan layouts and PFC features, I still felt people would be interested in my findings.

The three PSUs being tested (in increasing wattage order):
1) OCZ PowerStream 420 (Model # OCZ-420ADJ)
2) Cooler Master Real Power 450 (Model # RS-450-ACLY)
3) Enermax 550 (Model # EG651P-VE FMA)

I tested the PSUs with a PSU Testing Kit from SeaSonic, which includes a dual-mode PSU loader and a Power Angel, as well as a cap for activating the PSU without a motherboard or loader attached. The PSU loader has two settings: GPX (75.1 watts total, 12.0Amps on the +3.3V rail, 3.5Amps on the +5V rail and 1.5Amps on the +12V rail), and G (137.6 watts total, 12.0Amps on the +3.3V rail, 10.0Amps on the +5.5V rail and 4.0Amps on the +12V rail). All PSUs were tested for efficiency with both modes. Elementary listening tests were performed without the PSU loader, because the loader has an extremely loud fan in it. With the Power Angel, I recorded the AC voltage, current drawn in amps, watts power being consumed, VA (AC voltage * current drawn) and the resultant power factor, derived from dividing the wattage consumed by VA.

Ambient temperature during testing was 24C; all testing was done in open air.

For reference, here are figures from previous test on Antec Neo Power 480:

GPX Mode (75.1 watts load):
AC Voltage during test: 116.6 Volts
Current being drawn: 1.15 Amps
Watts power consumed: 132 watts
VA figure: 133
Power Factor: 0.99
Resultant Efficiency (75.1/132) = 56.9%

G Mode (137.6 watts load):
AC Voltage during test: 116.4 Volts
Current being drawn: 1.71 Amps
Watts power consumed: 199 watts
VA figure: 200
Power Factor: 0.99
Resultant Efficiency (137.6/199) = 69.1%

And now, here are my findings for the three PSUs tested this evening:

1) OCZ PowerStream 420:
GPX Mode (75.1 watts load):
AC Voltage during test: 119.0 Volts
Current being drawn: 1.54 Amps
Watts power consumed: 117 watts
VA figure: 183
Power Factor: 0.64
Resultant Efficiency (75.1/117) = 65.2%

G Mode (137.6 watts load):
AC Voltage during test: 118.5 Volts
Current being drawn: 2.45 Amps
Watts power consumed: 191 watts
VA figure: 290
Power Factor: 0.65
Resultant Efficiency (137.6/191) = 69.1%

2) Cooler Master Real Power 450 (w/Active PFC):
GPX Mode (75.1 watts load):
AC Voltage during test: 119.0 Volts
Current being drawn: 0.91 Amps
Watts power consumed: 106 watts
VA figure: 108
Power Factor: 0.97
Resultant Efficiency (75.1/106) = 70.8%

G Mode (137.6 watts load):
AC Voltage during test: 118.2 Volts
Current being drawn: 1.47 Amps
Watts power consumed: 173 watts
VA figure: 175
Power Factor: 0.98
Resultant Efficiency (137.6/173) = 79.5%

3) Enermax 550:
GPX Mode (75.1 watts load):
AC Voltage during test: 119.1 Volts
Current being drawn: 1.93 Amps
Watts power consumed: 110 watts
VA figure: 170
Power Factor: 0.65
Resultant Efficiency (75.1/110) = 68.3%

G Mode (137.6 watts load):
AC Voltage during test: 118.4 Volts
Current being drawn: 2.28 Amps
Watts power consumed: 178 watts
VA figure: 270
Power Factor: 0.65
Resultant Efficiency (137.6/177) = 77.7%

Quick, basic listening tests:
Please keep in mind that these PSUs have not yet been broken in; normally with my new listening tests, I'd run the fans for a minimum of 48 hours to break them in, but this time, all PSUs were tested brand spanking new.

1) OCZ PowerStream 420:
This PSU's dual 80mm fans proved to be the smoothest of the three PSUs, particularly considering that this PSU has the fastest spinning fans and moves the most air of the three tested models. However, the fact that they spin the fastest and move the most air also means that in this comparison, this PSU had the highest volume of sound output. The predominant part of the sound signature for this PSU is wind turbulence, followed by some middle-high frequency motor drone; again, the sound of this PSU was the smoothest of the three.
Take note: this PSU exhibited a screaming loud coil whine when tested with e PSU loader in G mode. It was the only test among all performed on all PSUs where there was coil whine, but the coil whine was unbelievable--quite likely the loudest coil whine I've ever heard!

2) Cooler Master Real Power 450:
The one 120mm fan on this PSU is marked as dual ball bearing, and the sound signature is proof of this. The predominant noise in the sound signature of this PSU's fan is a swishing bearing sound, or something one might describe as bearing chatter. The low speed fan, slowest of all the fans in the three compared PSUs, also prduced a mid-frequency hum or drone. While this PSU spun the slowest and, overall, made the lowest level of noise volume, it moved, bay far, the least amount of air, and the sound signature of this PSU proved to be the least smooth, and most inconsistent of all.

3) Enermax 550:
For listening tests on this PSU, I tried setting the adjustable fan speed knob out back to both, full speed and minimum speed. At full speed, this PSU was easily the loudest of the three, and very likely one of the loudest PSUs I've listened to in recent years; the amount of air being moved, however, definitely did not increase proportionally with the increase in sound--I do not recommend running this thing at full speed unless under dire circumstances.
At minimum fan speed setting, this PSU produced lower sound volume than the OCZ, but still more than the Cooler Master. Moreover, the sound signature of this PSU proved to vary depending on which direction you listened to it from. The reason for this is that the 92mm bottom feed intake fan and the 80mm exhaust fan out back sound completely different. The 92mm intake fan spun slower than the 80mm exhaust, and produced quite a bit of bearing chatter. The 80mm exhaust, on the other hand, did not produce much chatter, certainly not enough to hear over the mid-frequency drone it was putting out. While somewhat smoother sounding than the Cooler Master, it was certainly not as smooth as the OCZ in signature, but at the same time, was closer to the OCZ in noise volume than to the Cooler Master. The volume of air moved by this PSU was close to that of the OCZ, with both moving far more air than the Cooler Master.

Listening test subjective verdict:
Of course this really depends on matter of taste. I personally find that unsmooth fans, which wax and wane in volume or frequency, or produce an inconsistent noise in general, to be more displeasing than a smooth fan that happens to be louder or make more air turbulence noise. As such, the unsmooth Cooler Master, if installed in a system that did not block, dampen or cover up the sound of the PSU fan well, would probably annoy me the most. The Enermax's 92mm intake fan is less noticible than the 120mm fan on the Cooler Master, but the 80mm exhaust fan produces more mid-frequency whine/drone compared to the lower frequency sound of the Cooler Master. Being that the Enermax is somewhat smoother, but louder and higher frequency, I still prefer the Cooler Master's sound over the Enermax. Finally we come to the OCZ; I found that the pleasingly smooth air noise of this PSU was less bothersome, and more like background noise--far less in my face, even though it's louder, than the other two PSUs. Given a choice between these three, were I not to mod any of them, and just use them as is, I'd go for the OCZ--its non-bottom-feed design also happens to be far more conducive to PSU cold air ducting from the front of the case, and preventing CPU or GPU heat from entering the PSU, unlike with the other two, resulting in more ramping. On the other hand, given the option to mod, I believe the Cooler Master is the easiest to mod with a smoother, quieter 120mm fan such as a Globe 120, particularly given the fact that the fan connector inside the Cooler Master happens to, conveniently, already be 3-pin!

If memory serves me correctly, also consider that in terms of overall volume, all three of these models were louder than the Antec Neo Power tested several weeks back--but then again, it's been a while, so I'm not 100% sure.

Efficiency results analysis:
Looking at the efficiency figures, we can clearly see that the OCZ (which, btw, is supposedly a rebranded Top Power unit) is a step behind the other two. Of the two superior models, the Cooler Master is still up by a couple percentage points; however, the Cooler Master is the only PFC model in this comparison (other than the indirectly compared Antec Neo Power), and in combination with the highest efficiency figure, the Cooler Master easily places the least strain on your AC infrastructure, allowing for the least amount of cost in terms of electrical bill impact, and allowing for the usage of a cheaper/lesser VA UPS for protecting against power outages.

Final verdict:
Although this is, of course, subjective in many ways, I'd place the Cooler Master at first place, Enermax at second place and OCZ at third place in this comparison. Many reasons factor into this, including ease of modding, general quality, efficiency and power factor.

Please feel free to post comments, opinions etc. I look forward to them!

-Ed

PS: I wanted to add that several factors were left out, for the most part, in making my picks. First off, OCZ's PowerStream offers the highest bling quotient of the three, by far, with its gorgeous chromed gun metal finish. The adjustable rails are more geared towards overclockers, particularly those using BH-6-based memory that wish to push their memory beyond 3.2volts VDIMM and have boards/BIOSes that allow it. Also definitely worth of mention is the human interface panel that Cooler Master includes with the Real Power; this little item fits into your 3.5" drive bay and reports, live, a readout of your current wattage load on the PSU; this sort of information can prove quite useful! Finally, if you look at the Enermax PSU and consider the fact that the two loads were way below the, "sweet spot," for that model, its efficiency results prove all the more admirable.

Edward Ng · Post by **Edward Ng** » Mon Oct 18, 2004 3:51 pm

Looks like I did it again; made a post that just gets blank stares.

Is it too long?

cliche · Post by **cliche** » Tue Oct 19, 2004 3:11 am

Edward Ng wrote:

Looks like I did it again; made a post that just gets blank stares.

Is it too long?

keep up the good work, I just went to the relevant bits for me

bateslabel · Post by **bateslabel** » Wed Oct 20, 2004 12:20 pm

I'll wait for the final review of the Coolermaster. I asked about it in another thread. I just want to see if it would be a good choice for me, an overclocker. Want to see how the rails hold up.

Edward Ng · Post by **Edward Ng** » Wed Oct 20, 2004 12:56 pm

bateslabel wrote:...Want to see how the rails hold up.

And that is why we have Mike.

bateslabel · Post by **bateslabel** » Sat Oct 23, 2004 11:37 am

How's the reviews coming

DryFire · Post by **DryFire** » Sat Oct 23, 2004 1:14 pm

Very interesting ed. I always took ocz to be crap but i guess i may have to reconsider.

bateslabel · Post by **bateslabel** » Fri Nov 26, 2004 11:35 am

Are we ever going to see how the rails of the Coolermaster held up

?

Edward Ng · Post by **Edward Ng** » Fri Nov 26, 2004 1:30 pm

Mike's review of the Cooler Master...