On removing the top we see a very unique design. It’s laid out in such a way you can see each stage of the design as you look from left to right. I personally have never seen a PSU built like this, not even the 510 SLI. In design terms it’s exceptional and from talking with PC Power & Cooling I started to understand why it looks so different inside, for this is the first power supply to market with proprietary rails. It’s often been discussed amongst experts that for a power supply to truly perform we would need to see proprietary designs but the down side of this is the cost involved in designing the proprietary system. This rule extends to any proprietary system. PC Power & Cooling are the first to take on the challenge at ATX level and for this they should be applauded.

In the above picture we can see most of the important stages. To the right we can see the AC to DC process (full wave bridge rectifier). This is where AC is converted to DC current which is then passed through filter chokes (the copper ring dohnuts). These are responsible for removing any residual AC current.

At this point the circuitry on the 850 SSI splits into three distinct parallel circuits (the PCB's with the yellow transformers). Below details just one circuit so just remember that there are three circuits here which is a huge reason for the 850 SSI's raw performance.

For each of the three parallel circuits, current is stored in pre-FET capacitors, which are the large black MOSFETS with the white stripes. FET’s (Field Effect Transistors) are responsible for feeding the correct amount of power to the primary transformers. These are switched on and off at very high speeds to achieve there accuracy.

Current is then passed on to the primary side of the transformer and then onto the secondary side of the transformer (the large yellow blocks). This stage pulls the voltages down to the correct levels. In this case, +5V and +12V. Let me explain this in more detail as you are probably wondering why I haven't mention the +3.3V rail yet.

You can see three clearly defined stages above with the yellow transformers. The top stage is responsible for both the +3.3V and +5V lines and the other two stages are responsible for the four +12V rails. Two +12V rails will share one stage, so the middle stage is responsible for +12V1 and +12V2, while the lower stage handles +12V3 and +12V4. Both the +3.3V and +5V share the same circuit since the two voltages are close enough to pick them off the same circuit. A regulator is then used to produce the +3.3V feed.

At this point all stages are rectified once more and then stored in another set of capacitors. In the above picture you can just see the end of one of the stages and the green capacitors which are smaller than the initial set of capacitors to allow fast responses to the ever changing loads a PC can and will produce.

There are adjustable pots inside for the +3.3V, +5V and both the +12V rails (there are four rails but they are run off two separate circuits) but they are not accessible from the outside. I would assume these are not really meant to be played with this time round and have even been sealed. The enthusiasts out there will no doubt be a little miffed at this, but it does make sense. If you want to tamper with things that if incorrectly adjusted can damage the power supply then it should void your warranty. The people out there that know what they are doing will not be put off by these safety measures, but the curious yet ill informed will be.

One other note worthy menton is the ultra high quality RF sheidling which will help keep interference to a minimum. I've not seen sheilding of this quality used in any other power supplies other than PC Power & Cooling. By the way, the small white square thing you can just about see at the top right deep inside of the above image is the full wave rectifier.

To test the power supplies here I’ll use a 100% stable, overclocked testbed full of high quality, power consuming components The stable, overclocked testbed used was the following:

I will measure the 3.3V, 5V and 12V rails over a period of 120 minutes while running Prime95 & 3D Mark 2003 (looped) at the same time. This will make sure both the CPU and GPU’s are being taxed heavily. A multimeter will be used to take the readings. The pages following this page will be

The Power Supply in Use – This page will cover all the power supplies while in use. Things like the subjective noise levels and quirks of all the power supplies will be noted here. Noise levels and conclusions were dictated by my own ear. I have a low noise water cooled system and for this test I turned off all fans while on its max overclock. The hard drive is in a suspension enclosure which makes it almost inaudible. The only parts making any noticeable noise were the 7800GTX cards. Hopefully this information will allow you to appreciate that when I say a PSU is quiet, you won’t be disappointed on purchase. So many a review I’ve read where the reviewer had 12 delta fans in his rig, typing loudly over his self made hurricane: "THIS PSU ADDED NO ADDITIONAL NOISE TO MY RIG! ITS VERY QUIET"

The Test Results – All the test result charted and examined.

Considering the power on tap, this PSU is relatively quiet. If I were to compare it to the Turbo-Cool 510 SLI's noise output, of which was scrutinised on a test rig which consumed 60W less than the current test rig, I would have to say subjectively it is a good 4db quieter. It seems the efficiency and fan circuitry are doing a good job here. Because the 510 SLI and 850 SLI share the same fan I would imagine that if you do manage to get close to its 850W capacity it will no doubt increase to a similar sound level to the 510 SLI, or higher.

PC Power & Cooling braid all there leads to the highest quality and so it’s a joy to install and makes the inside of a PC look great. The extra 9cm in length this PSU has over typical designs does make it a little trickier to install but this will depend on the size and design of your case. All leads are of great length and will allow tidy cable routing.

There were no stability hiccups during testing at all. Fan noise did not increase during the full load testing either.

There is currently nothing else on he market that could be called competition to the 850 SSI. Zippy make some units that go up to 750W but it doesn't have the bells and whistle of this unit. The great thing about the Turbo-Cool range is there no compromise approach. You will be hard pressed to find yourself wanting more. Granted, it does cost a lot, at $449 / £300 but you are getting a proprietary design that will power anything you care to throw at it.

The rails are as good as anything I've tested to date and it fully outperforms the only other quad +12V railed unit I've tested, the Silverstone ST65ZF by a large margin. It also looks great being very similar in style to the 510 models. It's pretty much like the big brother to the 510 SLI, and so has excellent cable braiding. For those of you who have never had a PSU with braided cables you are missing out. This unit is the ultimate example of how it should be done.

The Turbo-Cool range has never been noted for there quiet operation but the 850 SSI attempts to change this. It is still not as quiet as a Seasonic or Enermax Noisetaker but this time round I can actually live with the noise, something I couldn't have done with the 510 SLI.

Efficiency is very important in a unit that is made to power 850 Watts of PC, and the 850 SSI is up there with the best of them with an 85% efficiency rating. It also has a 5 year warranty and all the connections you could ever want. When you start to conclude on this unit, it doesn’t remotely look like bad value.

 



This is the most powerful, most ambitious and most well designed unit I've had the pleasure of reviewing and it deserves an Editors Choice award on these merits alone!