PC Power & Cooling 750w Silencer S75EPS PSU Page: 1
Introduction

PC Power & Cooling are on the tip of every computer enthusiasts tongue when it comes to power supplies. Delivering nothing but stable power for the most power hungry machines since their launch back in 1986, their range of modern units such as the Silencer and Turbo-Cool have won many awards.

I recently had the pleasure of taking the Turbo-Cool 1kw unit for a test drive, and was thoroughly impressed with the stability of its voltages that remain unbeaten to date. The only gripe I had with the unit was it's high noise levels under load - something which I'm hoping PCP&C have alliveated in the Silencer 750w, which is on the OC3D test bed today.


Packaging

PCP&C have always liked to keep it plain and simple, packaging their units inside plain cardboard boxes printed with some basic specifications. This makes perfect sense as most PCP&C units are highly unlikely to make their way onto retailers shelves, and are instead either sold through PCP&C's website or one of their global distributors.

PCP&C 750w Silencer Box PCP&C 750w Silencer Box

The 750w Silencer arrived in a plain white, double-walled corrugated cardboard box very similar (but smaller) than the recently reviewed 1kw Turbo-Cool unit. The packaging does its job perfectly, protecting the unit from knocks and bumps during shipping - even on it's long journey from Carlsbad, USA.

We can see from the front of the box that the 750w Silencer boasts a peak output of 825w, 83% efficiency, 60 amps on the +12v rails and a metallic copper finish - very nice.

PCP&C 750w Silencer Packaging PCP&C 750w Silencer Package

The box is separated into 3 compartments for containing the power supply, cables and manual. It's great to see that the power supply is situated in the middle of the box, which should keep the unit safe from anything that pierces the cardboard during transit.

Removing the upper layer of cardboard reveals the Silencer unit in all of its glory. The unit is protected by a large plastic bag which should prevent any scratches or other marks from appearing on its funky copper paintjob.

PCP&C 750w Silencer Kit PCP&C 750w Silencer Leaflet

Included in the box were the following items:
• 1x PCP&C 750w Silencer unit.
• 1x Standard power cord.
• 4x ATX case screws.
• 1x Warranty leaflet.
• 1x Unit test report.

The included test report sheet contains all of results obtained from the testing of the power supply at the PCP&C factory. Just browsing over the page we can see some very impressive results from the rails under load and an efficiency of 83.02%.



PC Power & Cooling 750w Silencer S75EPS PSU Page: 2
Specifications

The following specification has been taken in most part from PC Power & Cooling's website:

Our new Silencer 750 EPS12V power supply gives you legendary PC Power and Cooling performance and reliability along with a unique ultra-quiet cooling design, brilliant copper finish, and a price that seals the deal.

• 750W @ 40C (825W peak)
• 90% less noise per watt
• EPS12V / nVidia SLI certified
• 83% efficiency with .99 PFC
• 12VDC output @ 60A
• 24, 8, 4-pin M/B connectors
• 2 PCI-E and 15 drive plugs
• Automatic fan speed control
• Copper finish (Black on request)
• 3-year warranty and support

Specifications

What I like most about the S75EPS is its single +12v rail layout which produces an amazing 60 amps. The biggest advantage of a single +12v rail is that you needn't worry about balancing the load from your devices across multiple rails. For this reason, the Silencer 750w is an ideal candidate for the high-end SLI or Crossfire setup.

Cable Layout

Impressively, the S75EPS manages to cram all of its components into a casing much the same size as a standard ATX power supply. The unit also boasts plenty of connectors with a minimal number of cables...but more on this over the next few pages.



PC Power & Cooling 750w Silencer S75EPS PSU Page: 3
Appearance

The first thing that strikes you about the Silencer 750w is its finish. Painted in metallic copper, the Silencer 750w sparkles like a bar of gold under direct light. Regardless of whether you love or hate the colour, it's clear to see that PCP&C have listened to computer enthusiasts who rant on how boring a matt black PSU is these days. For those of us who have a PC colour scheme not suited to this unit, PCP&C do still offer the Silencer 750w in a matt black finish on request.

Measuring in at 149x86x180mm (WxHxD) the Silencer 750w is roughly the same size as a standard ATX PSU, which is great news for those of us with small cases or limited space around the PSU area. The unit also felt very heavy in comparison with some of our previously tested power supplies, which is generally a sign of a good quality unit.

PCP&C 750w Silencer Back PCP&C 750w Silencer Top

The back of the unit contains an 80mm fan covered with a painted black mesh fan grill, which contrasts really well with the copper paintwork of the PSU. As with all other modern PSU's, the silencer is able to auto-detect the input voltage, and therefore has no switch to manually change the voltage between 110/230v.

A specifications sticker has been placed on top of the unit, which (in my opinion) is a much better place for the sticker, as it doesn't cover over the parts of the power supply you are likely to see with the unit installed inside your case.

PCP&C 750w Silencer Side PCP&C 750w Silencer Front

The sides and front of the unit contain several long, thin grills around the components that require air flow. Through the front of the unit it is possible to see the large aluminium heat sinks responsible for dissipating the heat from some of the hotter components.

The front of the unit also has a small lip with two wide screw holes. I can only assume that this can be used to bolt the end of the power supply to the top of a case, thus stopping the end of the power supply from 'sagging' downwards under the weight of its internal components.



PC Power & Cooling 750w Silencer S75EPS PSU Page: 4
Connectors

On the previously tested PCP&C Turbocool 1kw PSU, I was thoroughly impressed with the number of cables and connectors on the unit. Hopefully the Silencer 750w will follow in its big brothers footsteps - after all, what use is 750w of power if you don't have enough connectors to utilise it all!

PCP&C 750w Silencer Cables PCP&C 750w Silencer Cables

PCP&C 750w Silencer Cables PCP&C 750w Silencer Cables

It's good to see that PCP&C has professionally sleeved every cable right up to the first connector for better airflow and a tidier look. It would have been nice to see all cables fully sleeved up to the very end connector, but this would serve no purpose other than for cosmetics.

PCP&C 750w Silencer ATX PCP&C 750w Silencer EPS12V

The S750EPS comes with a 24-Pin ATX connector and no way of reducing the connector down to 20-Pin. This is most likely due to the unit being native EPS12v (as suggested by the unit's name). People wanting to use this unit on an older style 20-pin ATX motherboard will need to purchase a 24-Pin to 20-Pin connector seperately.

Quite a few of the most recently released motherboards still utilise the 4-Pin (P412v) connector, and for this reason PCP&C have included both P412v and EPS12v (8-pin) cables on the Silencer to ensure full compatibility.

ATX EPS12V PCI-E

SATA Molex Floppy



PC Power & Cooling 750w Silencer S75EPS PSU Page: 5
Looking Inside

As with all power supplies that pass through Overclock3D, I'll be taking a look inside the Silencer. By doing this I should be able to get a good idea of the overall build quality of the unit and how it is likely to perform in our tests.

PCP&C 750w Silencer Inside PCP&C 750w Silencer Inside

PCP&C 750w Silencer Inside PCP&C Silencer 750w Inside

I was quite surprised to see a rather spacious layout inside of the Silencer. The unused area around the cooling fan almost makes me wonder why they didn't reduce the size of the casing by around 10mm to make the PSU even more appealing to people with limited space inside their cases. However, the layout of the internal components combined with the two large aluminium heatsinks allows for excellent air flow through the unit.

I'm always on the lookout for adjustable pots in PSU's that pass through OC3D, as these can come in very handy on increasing the voltages if they droop under heavy load. Unfortunately I was unable to find any on the Silencer, which is a great shame considering most other PC Power & Cooling models have this feature.

PCP&C 750w Silencer Fan PCP&C 750w Silencer Fan

As previously mentioned, the Silencer is cooled by a single 80mm fan. A quick search of the internet turned up the following specifications for this fan:

• Dimensions: 80x80x25
• Bearing: BALL
• Speed: 3900rpm
• Airflow: 50.0cfm
• Noise: 41.0dBA

With a noise level of 41dBA when running at 12v, this is not the kind of fan I'd personally associate with silence. Hopefully PCP&C have ensured its quiet operation by keeping it at a low speed whenever possible - other wise we may have a noisy "Silencer" on our hands.



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Load Testing

In order for the results from all current and future PSU reviews to remain fair and comparable, Overclock3D uses a custom built Power Supply load stress tester.

The tester will be placing the following loads on each of the Silencer's rails:

+3.3v - 20a Load
+5.0v - 20a Load
+12v - 40a Load

The results are collected from a Mastech MAS-345 Multimeter which logs its readings via RS232 to a PC.

PCP&C 750w Silencer 3.3v PCP&C 750w Silencer 5v

Following in the footsteps of the recently reviewed Turbo-Cool 1kw, the Silencer exhibited no (yes ZERO) fluctuation on both the +3.3v and +5.0v rails. This is simply an amazing result, and something PCP&C should be very proud of.

PCP&C 750w Silencer 12v

Yet again the Silencer places its self among some of the best power supplies we've ever tested here at Overclock3D. With only 0.02v fluctuation on the +12v rail when placed under 40 amps load, this PSU is an ideal companion for those voltage sensitive graphics cards.


Efficiency Testing

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains against the power (in watts) consumed by the OC3D power supply stress tester.

The results may not be as accurate as those produced by professional testing equipment, but will certainly come in handy when comparing several power supplies against each other.

PCP&C Silencer 750w Efficiency

The S75EPS was placed under a load of 646 watts. This counts for a total of 86% of the power supplies rated output. At this load, the power supply required 779 watts from the mains to produce the 646 watts required by our custom made power supply tester. Therefore the efficiency of this power supply can be found by a simple equation: (646 / 779) * 100 that works out to be an efficiency rating of 82.9%.


Noise Testing

Possibly the hardest part of any PSU review is summarising the level of noise given out by the unit. The threshold for what is considered 'noisy' varies from person to person and therefore what I may consider a quiet unit, another person may consider extremely loud. A common way to resolve this issue is to use a dBA meter to measure the units noise level, however this doesn't take into account the pitch (type) of noise emitted and whether it is likely to irritate end users.

For this reason OC3D records all power supplies at idle and load in wav format for you to make your own informed decisions. All recordings are taken at 30cm away from the PSU and outside of a PC case. You will need to remember that noise levels will be reduced by varying amounts once the PSU has been installed inside your PC enclosure.

Idle Recording - Download
½ Load Recording - Download
Load Recording - Download

At idle I found the unit to be almost inaudible, even with my ear up close to the exhaust fan.

Increasing the load on the PSU to half of its rated output caused the fan controller to bump up the fan speed. However, at this speed the unit remained at a perfectly acceptable noise level which even a HTPC user would find hard to fault.

At full load the Silencer increased the fan speed by a significant amount, causing the noise levels to increase at the same time. Personally i would say that the noise output was on the verge of acceptable for my tollerances. It is worth remembering that the average user will find it hard to place the Silencer under this amount of stress, but in my opinion PCP&C could have chosen a better fan to cool the unit.



PC Power & Cooling 750w Silencer S75EPS PSU Page: 7
Conclusion

The PCP&C Silencer 750w is an amazing unit. Following in the footsteps of PCP&C's highly regarded Turbo-Cool range, the Silencer managed to breeze through our tests without even flinching. Rail stability was excellent, exhibiting little or no fluctuation what so ever - something we hardly ever see when placing PSU's on the OC3D test bed.

PCP&C have also managed to greatly improve the efficiency of the Silencer 750w over some of their previous units as you can see from the 82.9% result calculated by our tests. PCP&C have clearly proven that it is possible to have masses of stable power without breaking into a sweat when the electricity bill arrives.

The only real gripe that I have with this unit is its noise levels at full load. I was really hoping that the Silencer would be whisper quiet regardless of the load, but to expect this of a unit cooled by an 80mm fan is slighty unrealistic. It would be nice if PCP&C could reconsider the fan chosen for the S75EPS, as there are many fans available with better specifications than the ADDA. Maybe then I could award this unit the 100% it is so close to deserving.

The PCP&C Silencer 750w is in limited supply here in the UK, but thankfully can be purchased over at Extreme Prometeia for a reasonable £146.


Pro's
+ High efficiency results at 82.9%
+ Rock solid rails with little to no fluctuation.
+ Unique metallic copper painted finish.
+ Plenty of connectors
+ Well designed interior layout
+ Whisper quiet at idle and moderate loads.

Con's
- Fairly noisy under full load.
- No adjustable potentiometers (not that they are needed).


Editors Choice

Thanks to PC Power & Cooling for providing this unit for review.

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