HX620



The close-up above reveals we will be exmanining a power supply based on a multi-rail design. While this is not my favorite topic it's important we distiunguish between what is avialable and what certain guidelines dictate the manufacturer follow. For many years a 20-pin ATX power connector was all that was adequate to power any system, that is until the Pentium processors began demanding more current. Intel's solution was to introduce an additional 2x2-pin power adapter also known as the P4 power adpater. Next came PCIx bus and slot which required four additional pins transforming the 20-pin connector into a 24-pin connector supplying an additional 75W for the new bus and cards which ran off the PCIx slot. The evolution or mutation continued transforming the P4 to an 4x4-pin configuration to feed the voracious hunger of Intel's ever deepening pipelined beasts. The reasoning behind multi-rail designs are wrought with contradictions. However we cannot fault the manfacturrer for following guidelines and so we introduce what is certainly one of the finer executions of that design.



Corsair micro is widely known as the world's leader in desktop performance memory. While there are a multitude of other companies, many of which provide high quality products, Corsair has been very consistent in their role as a supplier of the worlds very best high performance memory. Products released over the years such as the TwinX, XMS, XMS Pro, Xpert and now Dominator Series of memory, all innovative, contributed a great deal to the industry while providing consumers with several options at the fastest speeds. Memory has certainly been Corsair's forte', however; they've also released several water-cooling systems which have been well accepted and perform on par with companies specializing in that field. Corsair's most recent divergence from the memory market has produced two new power supplies, the CMPSU-520HX, CMPSU-620HX both are modular, ergonomic and available internationally. As in the photo above, we test the HX620 which arrived in typical Corsair fashion, secure packaging.



Corsair has never suffered in the presentation department and they go to great length to ensure their products look as good as they perform. This they make evident on the box, since it is the first thing you see and for those whom dismiss "packaging" per se as superfluous, it's most likely because the company did their job correctly. It's usually not until you receive a damaged product you begin to ponder how securely it might, or should be boxed. PSU's are heavy and most arrive in thin bubble wrap and a tight fitted albeit thin cardboard box, which is fine if “double boxed” correctly. Corsair uses a thick form-fitted foam enclosure to secure the unit in place for travel. It costs more to do this, but it's less costly then an unhappy customer. In the photo below the top portion of the foam has been removed.



In the box is an 18AWG power cord which is adequate for maximum current draw. Cables are neatly tucked away in a sturdy pouch with Velcro fastening. It's a bit much for me but given the type of cables included, this is a nice storage place.



Cables provided are svelte in appearance and relatively flat, although not necessarily the type which would impede airflow through the case. While I'm not an advocate of modular cables these are the most ergonomic I've seen.



The cables connectors are especially unique accommodating their "flat" design. Much less cumbersome then any others I've used. And for those of you whom have tried to connect or disconnect modular cables inside your case, you know how difficult that can be.



I am not an advocate of modular cable designs as they introduce unnecessary points of resistance where oxidation can occur and repeated use of the plastic connectors leaves them prone to failure. Many Reviewers would disagree claiming the level of resistance is so minimal as to be inconsequential. I won't debate the subject here except to say; above 700W I wouldn't want designs featuring modular cables. Where the HX620 is concerned I am impressed with the cable system Corsair chose. It's unique, svelte, unobtrusive and most definitely User-friendly.



Specifications -->

Corsair HX620 Specifications



Corsair has replaced the atypical spec list at their site, with a list providing information in layman’s terms. I'm inclined to agree with their method since end-users in the market for a 520W or 620W PSU would most likely appeal to more mainstream users rather then a high-end gamers or overclockers.



It's not as if these power supplies don't pack a punch and with the HX620 SLI is definitely in the picture, however; with Geforce 8800 GTX graphic cards now hitting store shelves and quad core CPU already falling into reviewer’s hands, 1000W PSU's are becoming standard for the extreme user. The HX620 seems to have enough power to appeal to all sorts of people. Similar to its modular design, even specifications listed at the site are user-friendly. All the vital details are found here including efficiency, noise and power tables, seen in thumbnails below. The latter were taken directly from the site and HX series manual respectively.



For those who may resist change, or simply prefer the usual specification layout I've translated the data from Corsair's site into that format below.

Corsair HX620W PSU
Operating Range:	Universal AC input 90~264V automatically scans and detects the correct voltage.
Active Power Factor Correction:	0.99
Operating Frequency:	50-60Hz
Current:	10A
Efficiency:	Double forward switching - 80%
DC Output:	+5V @ 30A +12V1 @ 18A +12V2 @ 18A +12V3 @ 18A -12V @ 0.8A +3.3V @ 24A +5VSB @ 3A max combined wattage - 3.3V & 5V = 170W max combined wattage - 12V* = 600W total power = 620W
Safety Approvals:	UL, CUL, CE, CB, FCC Class B, TÜV, CCC, C-tick
Operating Temperature:	50ºC
Industrial Grade Capacitor Temp	105ºC (4 times the lifespan of conventional 85ºC rated capacitors)
Fan Type:	Ultra quiet 120mm double ball-bearing (varying RPM by temperature)
Noise:	19 - 35dB(A) / 10 - 100% LOAD respectively
Compatibility:	Supports the latest ATX12V v2.2 and EPS12V 2.91 standards and is backwards compatible with ATX12V 2.01 systems. Guaranteed compatibility with dual-GPU configurations
M/B Connectors:	24-pin, 8-pin, 4-pin, dual 6-pin Video
Drive (Assorted) Connectors:	8 Serial ATA connectors (4 on 520W), 1x2-Molex, 2x3-Molex, 1x2-floppy (Molex adapter), 1xMolex to Fan.
Dimensions:	5.9"(W) x 3.4"(H) X 5.9"(L) 150mm(W) x 86mm(H) x 150mm(L)
MTBF:	100,000 hours

Under the Hood:

At first glance the HX620 look's to be robust and well constructed. The circuitry is organized, capacitance is substantial, and the main transformer is significant.



Heat is our nemesis and the HX620 features a 120mm fan supplied by ADDA. It's quite powerful moving 85.2CFM at 39.1dB(A) which does present a noise concern, but certainly keeps things cool when needed. The fan is temperature controlled which does aid in noise reduction and proper cooling.



Under the Hood Continued -->

HX620 Circuitry

As stated previously the HX620's circuitry belies its power rating, in this case a compliment. Undoubtedly Corsair chose a reputable PSU maker and a solidly engineered design. In the thumbnails below the photo there's a close-up of the inductors, the primary capacitor (heatsink mounted transistor), main transformer and secondary transformers respectively.





Rotating the PSU to the DC-out lines the motherboard and CPU lines are straight forward with the remainder being modular. Note the use of additional capacitors and inductors which aid in smoothing out high frequency ripple and storage. In the thumbnails we see the "Split Rail" 12V guidelines are met, with a clear separation of the 12V1 and 12V2 solder point’s origination.





Here we take a closer look at the output stages where they lead to the modular connector slave-PCB. It’s from that board that the modular connector power is distributed. The number of junction/solder points where the wiring is interrupted introduces resistance and is my reasoning behind a preference for uninterrupted wiring. The HX620 doesn't look to be a PSU in which the resistance should affect performance, and it's doubtful this could be measured without sensitive equipment.





Testing / Conclusion -->

Test Setup / Conclusion



I ended up testing the HX620 over a period of several weeks and across several systems, including the AOpen i975X a-YDG / Yonah 2600ES. Due to its low power consumption I eschewed that system from test results. Most reviewers have a very limited amount of time with which to test products. While I certainly do not think it's feasible to test all products for extended periods, testing a product for a few days does not, in my opinion, give an accurate result. I learned a great deal about electronics and electronic circuitry from my Audiophile days. Of paramount importance was the critical "break-in period." This was especially true in high end audio since one would literally "hear" components breaking in.

As the expansion and contraction of molecules effects micro-circuits, so too does this transformation affect the sound produced by those components. Tonality, depth, high's, low's, midrange and perhaps most dramatic, the ability to image. This is especially true with solid state hardware such as Krell stereo amplifiers which may sound rather harsh out of the box until the circuits break in, at which time the sound has undergone a literal metamorphosis. This is the reason most high end amplifiers never really shut-down, instead they utilize stand-by switches which trickle low levels of current keeping transistors and devices "warm." For the same reasons it's better to leave all electronics, including your PC on if used daily. And for the same reason I feel testing products in less then 5-days just doesn't bode well, nor does it give an accurate picture of performance, not to mention longevity.

1. Intel / 2. AM2 Test Systems:
CPUs	1. Intel Conroe 6400 Retail Socket-775 2. AM2 3800X2 Retail
Mainboards	1. Asus P5W DH Deluxe (BIOS 1506) 2. Asus M2N32-SLI Deluxe/Wireless (BIOS 0706)
Memory	1. Crucial Ballistix PC2-8000 (2028MB) 2. Super Talent PC2-8000 T1000-UX2G4 (2x2048MB)
Graphics	1. AOpen Aeolus 7800GTX-DVD256 2. Leadtek PX7950GX2 TDH (2x) QUAD-SLI
Power Supply	1. Corsair CMPSU-620HX 2. PCPower&Cooling Silencer 750EPS12V 3. Silverstone Zeus ST85ZF
Cooling	1. Swiftech Apex Ultra 2. Danger Den NVIDIA 4101-kit
Storage	1. Maxtor 300GB SATA 2. 2x Seagate Barracuda 80GB SATA Perpendicular
Optical	1. Plextor PX-755SA DVD/RW 2. NEC DVD/RW
Operating System	Windows XP Home SP2+

Testing the HX620 consisted of powering two separate systems.

First in our Core Duo E6400 / Asus P5W DH Dlx and then an AM2 3800X2 / Asus M2N32-SLI Dlx. On the latter I ran two Leadtek PX7950GX2-TDH graphic cards in pseudo-QUAD SLI (pseudo since it's not four individual cards). On the Core Duo E6400 / P5W DH Dlx system a single AOpen Aeolus 7800GTX card was used. Measuring DC-voltages the Extech Minitech MN-26 leads were inserted into the reverse end of the 24-pin motherboard connector and 4-pin baseboard (CPU) connector as well as measuring Molex and 6-pin external video. Each system was run at default speed and then overclocked with all measurements recorded at full LOAD. On processor's this was produced using the program S&M v. 1.8.2. (160)

Noise measurements were taken using the Smart Sensor AR-824 SPL meter from a distance of 1-meter. For this test the following results were obtained. Ambient room noise = 31dB(A)
Test system 1. 3800X2 - Asus M2N32-SLI Dlx
Default speed - Idle = 39dB(A)
Default speed - LOAD = 42dB(A)
Overclocked - Idle = 39dB(A)
Overclocked - LOAD = 43dB(A)
Test system 2. Core Duo E6400 - Asus P5W DH Dlx
Default speed - Idle = 33dB(A)
Default speed - LOAD = 34dB(A)
Overclocked - Idle = 33dB(A)
Overclocked - LOAD = 36dB(A)

The large discrepancy in noise between the Core Duo and 3800X2 was due to the AM2 system running in QUAD SLI which constantly taxed the unit despite or regardless of, CPU speed. Onto voltages.



Conclusion:

To be honest I tend to cringe whenever I learn a specialty company in the technology sector decides on a quick product diversification when demand for said product happens to be up. It's often been the case a company is simply seeking to profit off their reputation which is not only a gamble, they often loose respect with more astute consumers who know they haven't built a better mousetrap, they've simply made one with a slightly better cheese holder.

In this case I have a one word - one acronym answer: QUAD SLI. The fact this PSU was able to power two Leadtek 7950GX2's in SLI (QUAD) while the AM2 3800X2 was overclocked to 300FSB says it all. Corsair isn't a PSU "maker" however I do applaud their effort to seek out a solid design, one which does belie its power rating to your advantage. The extra kick is most likely the result of "Load Sharing" which allows power from one rail to combine with another when taxed beyond its 18A limit. While I do see this as an ad hoc fix, it is a common work-around to design limitations inherent in the ATX/EPS12V Power Supply Guides. Corsair has incorporated an unique, user friendly modular cable system, with a fairly powerful multiple rail power supply. I must admit I was impressed.

PRO
Powerful, SLI no problem
Solid rails, minor fluctuation
User friendly, svelte modular design
Doesn't add much to overall system noise.

CON
Pricey

At the time of writing Corsair's CMPSU-620HX can be found at Newegg for $179

Questions/Comments: forum thread