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Review: Battle of the 1000W PSUs: Corsair HX1000W vs. AKASA PowerMax V2

by Tarinder Sandhu on 22 April 2008, 00:04

Tags: HX1000W, PowerMax V2, Akasa, Corsair

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Corsair HX1000W


Fundamentally, a 1kW PSU will be able to drive, effortlessly, a three- or four-GPU graphics susbsystem; the latest power-sucker from Intel and AMD; a dozen hard drives, and more memory than you can shake a stick at - something like Intel's Skulltrail platform, for example.

Indeed, only enthusiasts who wish to power outrageous cooling, on top of significant hardware, may need more. Put simply, the 1kW+ PSUs are the Rolls Royces, and manufacturers have charged accordingly.

We alluded to the fact that a PSU's wattage rating shouldn't be the only metric for comparison. Build quality; significant amperage on the 12V rail(s), multifarious connectors; continuous load at high ambient temperatures; and (relative) fan quietness at mid-range wattages are some of the characteristics we'd be looking for.

Corsair HX1000W

Corsair first shipped company-branded power supplies last year. The range now encompasses seven models, and all have passed the 80 PLUS certification, meaning that all PSUs operate at 80 per cent, or above, efficiency over a wide-load range - 20pc, 50pc, and 100pc of stated power output.

Now, Corsair doesn't manufacture the PSUs directly. Rather, it negotiates a contract for a base model from one of the large Taiwanese firms and then has its engineers pore over the details, looking at how the design can be improved with respect to performance and longevity. Once happy, the PSU(s) is manufactured to Corsair's specification and branded up.

We first saw the pre-production 1,000W model at this year's CES show. At that time, it was running a three-way SLI subsystem, and mass-production was noted to be at the end of Q1 2008.

Corsair HX1000W
Rated output power 1,000W @ up to 50°C
Power specification ATX 2.2/EPS12 v2.91
Power switch Yes
Input voltage (AC) Autoranging 90-264v, 47-63Hz
Fan(s) 1 x 140mm
Operating temperature range 0-50°C
Cable runs

24-pin EATX (split)
EPS (8-pin with split)
EPS (8-pin, modular)

1 x 6+2 PEG (non-modular)
1 x 6+2 PEG (non-modular)
1 x 6-pin PEG (modular)
1 x 6-pin PEG (modular)
1 x 8-pin PEG (modular)
1 x 8-pin PEG (modular)

2 x 4-pin Molex, (modular)
2 x 4-pin Molex (modular)
4 x 4-pin Molex, 1x floppy (modular)
4 x 4-pin Molex, 1x floppy (modular)
2 x SATA (modular)
2 x SATA (modular)
4 x SATA (modular)
4x SATA (modular)

Max. currents

+3.3V: 30A
+5V: 30A
+12V: 80A (40+40)
-12V: 0.8A
+5vSB: 3.5A

Max combined 3.3V & 5V output N/A
Dimension (W x H x L) 150 x 86 x 200mm
Warranty 5-year, limited
Price £146

The twin-rail (12V) PSU is certified for three-way SLI and twin GeForce 9800GX2, according to NVIDIA's literature, yet it doesn't appear on ATI's approved CrossFireX list, strangely.

Basic design is taken from, as far as we can discern, a Channel Well Technology (CWT) 1.2kW PSU and tweaked extensively.

Looking at the specification table, the rated output of 1,000W is guaranteed at an up-to ambient 50°C, which is excellent. The base 1,200W PSU has been modified to offer a lower sustained wattage but with higher tolerances, it seems.

A couple of EPS12V connectors means that you can hook it up to dual-CPU boards such as the Intel D5400XS - the base for Skulltrail.

A single, thermally-controlled 140mm double-ball-bearing fan is reckoned to produce only 24dB when running up to 500W, rising to 44dB at 1kW.

The large fan dominates the simple styling.

The modular PSU measures 150mm x 86mm x 200mm (W x H x L). The ATX specification states a length of 140mm (146mm with support brackets) as the maximum, making the Corsair a touch bigger and essentially EPS sized. Some smaller chassis may therefore have trouble accomodating its length.

Corsair specifies Japanese-made capacitors with a 105°C rating, we note, and the PSU uses two completely separate 12V rails, from distinct transformers, which can be thought of as mini-PSUs themselves, to power your goodies. The 3.3V and 5V lines are also derived directly from the 12Vs', by the way (DC-to-DC conversion).

Both 12V lines offer a healthy 40A each (480W), and one can have the non-modular cabling - 24-pin EATX, EPS12V (8-pin), and two 6+2 PEGs - complemented by an additional four PEG-oriented and six peripheral runs

Thinking of the modular connectors and on top of the two 6+2 non-modular runs, our review sample shipped with two 6-pin PEG cables and two (no-split) 8-pin PEGs, contrary to the four 8-pin (6+2) quoted by Corsair.

Corsair changed its configuration in the wake of the ill-fitting GeForce 9800 GTX and GX2's connectors, but will now change back to an all-6+2 setup in due course, when NVIDIA follows the industry-standard body, PCI-SIG, and runs 6+2, too. Phew!

Speaking of accessories and runs (and not referring to tummy trouble), here's what you get.....