PC Power & Cooling Silencer 750w CrossFire Edition ATX PSU Page: 1 Introduction
Back in May of this year Overclock3D were one of the first to bring you the news of PC Power & Cooling's acquisition by enthusiast orientated memory manufacturer OCZ Technologies. This monumental joining of forces vastly extended PCP&C's global reach, allowing them to distribute their high-end power supply's the world over using OCZ's well established networks. In addition to this, the once premium price tag of PCP&C's quality PSU lineup took a cut in order to bring them head-to-head with the competition - making a lot of PC enthusiasts very, very happy.
Taking a few steps back in time, Overclock3D first got a chance to sample the quality of PCP&C in May 2006 when we reviewed their Turbo-Cool TC1KW 1000w unit. Walking away with our highly regarded 'Editors Choice' award and let down only by it's price tag, the review simply reinforced the common knowledge that "you get what you pay for". Just four months later PCP&C released a slightly tamer version of the TC1KW in the form of the S75EPS 750w Silencer unit. Once again the power supply sailed through our testing, nabbing yet another 'Editors Choice' award.
Almost a year down the line (and no doubt with OCZ's influence), PCP&C have added yet another 750w Silencer unit to their portfolio aptly named the S75CF. Essentially an updated version of the S75EPS, the S75CF features connectors for the latest graphics cards, the same build quality as its elder brothers and an even cooler paintjob!
Anyway, enough of my ramblings. For the benefit of those who have yet to be acquainted with PC Power & Cooling, here's a brief history lesson from their website:
On April 19,1985, PC Power & Cooling began operations in a small warehouse just outside of San Diego, CA. Founded by Doug Dodson, a commodity trader and electronic hobbyist, the company's first products were custom fans to cool and quiet computers.
In 1986, the company introduced its Silencer 150 and Turbo-Cool 200, the industry's first ultra-quiet and high-performance power supplies. Other high-end products followed, the reviews were great, and the company continued to grow. In 1991, the company moved to a modern facility in Carlsbad, CA.
Over the last 22 years, PC Power & Cooling has produced many innovative products including: the first CPU cooler, the first PC heat alarm, the first independently-regulated PC power supply, the first redundant power system, the first NVIDIA-certified SLI supply, the first One Kilowatt computer power supply, and the first power supply with its own certified test report (Turbo-Cool 1KW).
PC Power & Cooling have always been extremely open when it comes to revealing the specifications of their PSU's. The information available on their website and in their specification PDF's is a refreshing change to the tactics of some companies who, for some reason, want to keep this information from the public eye. The following information shown below can all be found here and here.
The all-new Silencer® 750 Quad power supply series gives you legendary PC Power and Cooling performance and reliability along with a unique ultra-quiet cooling design and a price that seals the deal.The matching brilliant Ferrari red exterior of this special edition Silencer 750 PSU will look amazing in your CrossFire based high-performance graphics system or gaming rig.
• 750W Continuous @ 40C (825W Peak) • Up to 90% (10dB) Less Noise per Watt • ATI CrossFire Certified (HD 2900XT) • High Efficiency (83%); .99 Active PFC • +12VDC @ 60A (Powerful Single Rail) • Rock-Solid, Super-Clean DC Output • 24-pin, 8-pin, 4-pin M/B Connectors • Quad PCI-E and 15 Drive Connectors • Automatic Fan Speed Control Circuit • 3-Year Warranty and Tech Support
With many manufacturers designing PSU's containing six or more +12v rails, you may find it strange why PC Power & Cooling have never really embraced this idea - instead sticking to single, double or triple rail designs. However, there is a method to their madness and it ensures that no matter what hardware configuration you have, as long as the total current draw on the +12v rail is below 60amps, your system will not be starved of juice.
For example: Take a ~700w PSU that is designed with three +12v rails. The power distribution between those rails is likely to be around 28amps per +12v rail with a maximum draw of 60a across all three rails. If any one of these rails exceeds its 28amp rated output the PSU will trip OCP (Over Current Protection) and power off. This is obviously not a problem for single rail PSU's as all of their power is available to all devices on a single rail.
It's good to see that PCP&C have managed to fit the S75CF into a relatively standard sized ATX housing, maximising its compatibility with smaller PC cases. We can also see the reasoning behind the S75CF's "Quad" naming: A total of 4x PCI-E connectors are provided - two of which can be used with the latest 8-Pin PCI-E powered graphics cards.
PC Power & Cooling Silencer 750w CrossFire Edition ATX PSU Page: 2 Packaging
PC Power & Cooling have never really gone for the fancy retail packaging idea, instead sticking to very sturdy oversized cardboard boxes. It's no surprise either, considering PCP&C originally designed many of their units for enterprise servers rather than enthusiast PC's.
The Silencer 750w Quad arrived in a plain white, double-walled corrugated cardboard box that does a very good job of 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, Quad PCI-E connectors and a 3yr warranty.
The box is separated into 3 compartments for containing the power supply, cables and manual. It's good to see that PCP&C have situated the power supply in the middle of the box, further protecting the unit from any courier inflicted damage.
Removing the upper layer of cardboard reveals the S75CF in all its glory. We won't say much about its appearance just yet, but we can see that PCP&C have sealed it inside a clear plastic bag to prevent any minor scratching to the paintwork. Also included in the box are 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 rating of 84.56%.
Known for their 'no nonsense' approach to manufacturing PSU's, PCP&C have very rarely ventured outside the safe confines of a plain black powder coated finish. However, on relasing the S75CF it's clear that they wanted to do something special for ATI fans. Finished in what PCP&C describe as a "Ferrari Red" powder coat finish, the S75CF looks simply gorgeous (but then I'm a big fanof Red) and the black fan grill and screws contrast extremely well. For those of us who have a PC colour scheme not suited to this unit, PCP&C do offer the Silencer 750w Quad in a matt black finish at a slightly cheaper price.
In keeping with all previous PCP&C units, the S75CF features a single 80mm fan at the back of the unit. PCP&C believe this design to be superior to the top-mounted 120mm fan design used by other manufacturers as it does not restrict the vertical space available to components such as heatsinks and capacitors.
As we can see from above, PCP&C have placed the specifications sticker at the top of the unit rather than at the side like most manufacturers. This has the advantage of not covering over the side of the power supply you are likely to see once it is installed in your case.
The front of the unit contains two rows of long thin grills that provide airflow to the components inside. Through these grills we can just about catch a glimpse of two large aluminium heatsinks and one of the transformers. A wire guard has also been used where the cables enter the unit, preventing the metal casing from cutting into the wires and avoiding chipping of the paintwork.
PC Power & Cooling Silencer 750w CrossFire Edition ATX PSU Page: 3 Internal Components
In the past, many people have judged the quality of a PSU on its weight and size of internal components. However, with many manufacturers moving on to newer and more efficient ways of designing their PSU's, it has become increasingly obvious that this is no longer a reliable method for gauging a power supply's quality. By looking inside the S75CF we should be able to identifty some of the components used and get a good feel for the overall build quality of the unit.
The internal layout of the S75CF is fairly spacious, with plenty of room between the 80mm fan and component board to help prevent any cooling dead spots. Attached to the banks of mosfets at the center of the unit are two large aluminium heatspreaders that almost touch the top of the casing, and are finned in a way that compliments the direction of airflow through the unit.
Sandwiched between the heatsinsks are two transformers and a capacitor. The larger of the two transformers (left) is most likely responsible for the single 60amp +12v rail, with the smaller transformer (upper-right) responsible for both the +3.3v and +5v rails. At the centre is a large black capacitor manufactured by Japanese company Nippon Chemi-con.
Since the widespread adoption of the 120mm fan design over the past few years, the 80mm design has taken a bit of a back seat. Many manufacturers believe that the 120mm design offers lower noise levels along with increased airflow. However, PCP&C have a different view on this matter:
Most low-noise ATX power supplies today utilize a top-mounted 120mm fan rather than a rear-mounted 80mm fan. The 120’s favorable reputation is based on the fact that under low to medium load conditions, the 120mm fan provides sufficient cooling at low RPM and low RPM fans are generally very quiet.
However, problems occur with this design when the load exceeds 50%-60%. Because the 120mm fan consumes about 1.5” of vertical space inside the PSU, heat sinks, capacitors, and other components are about 30% smaller in height compared to a PSU with a rear-mounted fan. The smaller parts can handle less current, so the maximum power available with the 120mm design is limited. And, because the heat sinks have less surface area, more air flow is needed with this design to keep the thermal situation under control. With 80%-100% load, the 120’s fan speed can double and the noise level can jump by up to 20dB.
With this in mind, let's take a look at the specifications of the ADDA manufactured 80mm fan used inside the S75CF:
In previous reviews, PC Power & Cooling units have never been short of cables or connectors. After all, there's litte use in having a 750w power supply if you cant connect it to all of the devices in your system. We already know that the S75CF has quad PCI-E connectors, but let's take a closer look at what else is included..
If there's one thing I love about the way PCP&C package their PSU's, it has to be the use of a bog standard brown elastic band keeping all of the cables together. It just reinforces the fact that PCP&C would rather spend their time making the product rather than the packaging, and in a way almost feels like a 'fingers up' to manufacturers that go over the top on their packaging designs.
It's also 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 cosmetic appeal.
The S75CF comes with a 24-Pin ATX connector and no way of reducing the connector down to 20-Pin. 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 separately. 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 (4-pin) and EPS12v (8-pin) cables on the S75CF to ensure full compatibility.
With new graphics cards hitting the market that make use of the 8-Pin PCI-E connector it's good to see that PCP&C have provided two connectors that can be used in this format. For those of us who require 4x 6-Pin PCI-E connectors for configurations such a dual 8800GTX grapics cards, the 8-Pin connectors can be reduced to 6-Pin by simply snapping away the extra two blocks at the end of the connector.
PC Power & Cooling Silencer 750w CrossFire Edition ATX PSU Page: 4 Load & Efficiency Tests
To provide our readers with the most accurate results, Overclock3D uses a custom built PSU load tester on all reviews. This not only gives much more reliable results than the testing methods employed by other sites, but also allows for all current and future review results to be compared side-by-side.
Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.
With a maximum fluctuation of 0.11v, 0.08v and 0.02v on the +12v, +5v and +3.3v rails between 0% and 100% load conditions, it's fair to say that the PC Power & Cooling Silencer 750w Quad performed admirably. This once again goes to show that PCP&C are commited to manufacturing some of the best power supply's available.
PC Power & Cooling have never been a manufacturer that I'd associate with efficiency, however with the S75CF it looks like that is about to change. Managing 83.43% under 50% load and an even more impressive 84.08% efficiency under 100% load, the S75CF is actually one of the most efficient PSU's we've ever tested.
In our continuing efforts to make power supply reviews more thorough, rather than simply checking voltage stability, Overclock3D will now be recording the temerature of each PSU as it undergoes testing. Temperature recordings will be taken from the underside of the PSU's outer casing at 0%, 50% and 100% load levels using a laser infrared thermometer in an attempt to gauge how much heat is likely to radiate into the end-users case.
Despite the use of a single 80mm fan, the S75CF never displayed signs of any potential cooling problems. At 100% load the temperature taken from the PSU casing was 35°c (13°c above ambient), showing that only a small amount of heat would be dumped into a PC enclosure.
Noise Level Recordings
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.
As you will be able to hear from the recordings above, the S75CF managed to remain extremely silent at both 0% and 50% load levels despite the use of an 80mm fan. In fact, I have no doubts that installing the S75CF inside an average PC would see the noise from the unit drowned out by normal case, motherboard and GPU fans.
Increasing the load to 100% saw the fan speed elevate significantly, causing a rise in the noise levels emitted from the unit. In all fairness it would be extremely difficult for the average PC enthusiast to put this much load on the PSU, but at this load level the S75CF wouldn't be suitable for 'Silent PC' enthusiasts or those building a HTPC.
PC Power & Cooling Silencer 750w CrossFire Edition ATX PSU Page: 5 Conclusion
Having reviewed both the TC1KW and the S75EPS back in 2006 I was extremely interested to see what changes, if any, had been made to the PC Power & Cooling lineup since their partnership with OCZ.
First and foremost, the S75CF offers great voltage stability, with no rail fluctuating more than 0.11v and all rails remaining within their 'ideal' voltages. In addition to this the efficiency of the S75CF is one of the best we've seen here at Overclock3D, managing 83.43% at 443w load and a highly impressive 84.08% at 766w load. Topping off the package is some very sexy "Ferrari Red" paintwork designed for the ATI enthusiasts or indeed anybody who fancies a break away from the boring matt black units we are all too familiar with.
Priced at around £130, the S75CF is close to the top end of the price range for a ~750w unit, but as we always say "you get what you pay for". Unfortunately none of our recommended retailers stock the unit at present, but we hope for this to change in the near future.
So in summary, the PCP&C Silencer 750 CrossFire Edition is every bit as good as its predecessors offering not only voltage stability but efficiency, looks; and thanks to OCZ's global distribution networks, better value for money.
The Good • Top performance with excellent voltage stability. • Impressive 84% efficiency offers savings on those dreaded electricity bills. • 'Crossfire' version comes complete with sexy Ferrari red paintwork. • Single +12v rail ensures you'll never have problems with uneven load across multiple rails. • Extremely silent at 0% and 50% load levels.
The Mediocre • Noise levels at 100% load may not be acceptable to those who seek total silence. • Price a little higher than most manufacturers, but the quality is worth every penny.