Corsair HX850W (850w) ATX PSU

Cables, Connectors & Internals
The HX850W is fitted with a total of ten modular headers, four of which (the blue ones) are dedicated to PCI-E graphics card power, while the remaining six are for SATA/Molex based devices. Unlike the HX1000W, the HX850W is equipped with a single +12v rail removing the need for any kind of ‘layout’ sticker next to the modular headers informing users which rail each plug is attached to.
Corsair HX850 Modular Connectors Corsair HX850 Modular Connectors
In addition to the modular connectors, several cables are hard wired into the unit. These include the ATX, EPS-12v and 2x PCI-E connectors which are pretty much the bare minimum required connectors for powering any PC system. Having these essential cables ‘hard-wired’ is also a good thing as it not only ensures that critical system components get a good; clean supply of power direct from the PSU, but also avoids potential situations where an ill-fitted modular cable could cause system instability or even kill components.
Corsair HX850W Connectors  ATX Connector Native 1x 20+4 Pin  EPS-12v / P4-12v Connector(s) Native 1x 4+4 Pin  Molex Connectors Modular 12x  Floppy Disk Connectors Modular 2x  SATA Connectors Modular 12x  PCI-E Connectors Native / Modular 2x 6+2 Pin / 4x 6+2 Pin
Corsair HX850w Modular Cables Bag Corsair HX850w Modular Cables
Ten modular cables are included inside the canvas pouch which means, yes, you can plug each and every cable provided with the HX850W in at the same time. Not that you’d probably ever need to anyway, unless of course you can find a use for 12x SATA and 12x Molex cables inside your system? No, neither could I – but I’m sure some saddo is going to go out of his way to prove me wrong by sending in pictures of his 24 disk RAID array now.
Corsair HX850W ATX Corsair HX850W PCI-E
Corsair HX850W PCI-E Corsair HX850W Cables

The 24-Pin ATX and 8-Pin EPS-12v connectors both have the ability to be ‘broken down’ to the older 20-Pin / 4-Pin standards to provide full support for older motherboards. This is also the case for the PCI-E connectors (both hard-wired and modular) which can function in either 8-pin format or 6-Pin format, making the HX850W absolutely perfect for any kind of multi-GPU setup.

On thing I almost forgot to mention (which deserves a slap on my wrist because it’s so awesome) is the modular cables themselves. As with the rest of the HX line-up Corsair have chosen to construct these cables from an almost ‘ribbon cable’ style wiring where all of the wires are coloured black and moulded together in a flat ribbon style. This is much better than the traditional sleeving and heatshrink job you see on most modular PSU’s and should go a long way to improving the internal appearance of any enthusiasts PC.
Corsair HX850W Internals Corsair HX850W Internals
And here’s the money shots! The internal layout of the HX850W is extremely tidy with a slightly unconventional design PCB in the shape of a reversed ‘L’. This appears to have been done so that Corsair could squeeze in an additional primary capacitor at the front of the unit while only having to make a few small adjustments to the modular connector backplane to accommodate it.
Corsair HX850W Internals Corsair HX850w Internals
Two green transformers sit in the middle of the unit with the larger of the two being responsible for all of the main rails. The smaller one’s sole purpose in life is to power the +5VSB rail which is used mainly for USB headers and certain parts of the PC system while in Standby.
Either side of the transformers are two thin alumimim blocks used as heatsinks. These differ immensely from the oversized ‘finned’ heatsinks seen in most other PSU’s, which tells me that the HX850W is going to be one extremely cool running unit. Either that or Corsair forgot to install heatsinks and I’m going to get my face burned off!
Corsair HX850W Capacitors Corsair HX850W Secondary Caps
The primary and secondary capacitors are Japanese manufactured Nippon Chemi-Con KZE’s rated at 105°C. The primary caps carry specs of  330uF 420VDC, while the specs of the secondary caps are quite a bit more elusive with the only visible info being 200uF. Regardless, these caps are seriously high quality and should ensure trouble free operation for quite some time in the future.
Corsair HX850W DC-DC Conversion Corsair HX850W Model #
Nestled in between one of the heatsinks and a bundle of cables are the DC-DC boards. These are responsible for taking the PSU’s primary +12v output and stepping it down to +3.3v and +5v rails for the rest of the rails. Several Solid state caps have been used here (in fact the only place in the whole PSU) which is probably more down to space limitations than any kind of quality measures.  Also visible nearby is the PCB model number marked as CMPSU-XXXHX….see I told you this was PSU porn.
Corsair HX850W Fan Corsair HX850W Fan
Cooling is delivered by a 140mm Yate Loon fan with model number D14BH-12. Specifications taken from Yate Loon’s website reveal the fan to be capable of pushing 140CFM at 48.5dBA. Why the HX850W needs a fan with this much grunt is beyond me, but Corsair state that the fan doesn’t begin to ramp up until the unit hits 550w. So I’m guessing that at low speeds it may deliver slightly better performance than other models.
Now let’s move on to the testing and find out if all these fancy components actually result in decent performance.