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To ensure that the power supplies receive a full workout that can be controlled in a granular fashion, both were connected to a testing harness that loads lines whichever way we like.
| Readings under load | Power & efficiency | Temperatures | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PSU | +12V1 | +12V2 | +5V | +3.3V | -12V | +5VSB | Input power | Ideal output | Actual output | Efficiency | Ambient temp. | PSU temp (start) | PSU temp (finish) | Temp. delta | |
| Corsair HX1000W | Voltage | 11.965 | 11.93 | 5.015 | 3.247 | -12.312 | 4.95 | 1154 | 1004.5 | 1000.12 | 86.7% | 22.5 | 22.5 | 43.5 | 21 |
| Current | 40 | 40 | 4 | 5 | 0.25 | 1 | |||||||||
| AKASA PowerMAX 1000 | Voltage | 11.882 | 11.81 | 5.022 | 3.21 | -12.09 | 4.942 | 1175 | 1012.4 | 1000.43 | 85.1% | 20.5 | 20.5 | 45 | 24.5 |
| Current | 35 | 35 | 21 | 18 | 0.25 | 1 | |||||||||
Performance
The results make for encouraging reading for both camps. Stressed to their rated output, both PSUs provide strong lines across the board, with the Corsair a smidgeon closer to the rated values.
Efficiency, too, is excellent for both; over 85 per cent in both cases. The Corsair HX1000W runs a touch cooler than the AKASA, although the latter's readings aren't anything to worry about.
Both PSUs feature the triumvirate of over-current/voltage/power protection, enabling the PSU to auto-shutdown should matters go awry. However, testing with the Corsair we found that there was no OCP (overcurrent protection) on the 12V rails, and Corsair's reasoning lies with the ability of graphics cards to temporarily pull huge currents. Corsair claims that enforcing an OCP would mean risking the PSU tripping when games are fired up. We're not so sure, OCP protection should only kick-in after a short period of time and wouldn't therefore get tripped by the inrush current, we believe.
Further, the OPP (overpower protection) seems inadequate as it will only shut-down when the total power-draw exceeds 135 per cent of the total capacity, which in this case would be 1350W - a highly unlikely occurrence.
Noise
In the unlikely event of continually running the PSUs at 1kW - and, remember, our twin-card GeForce 9800 GX2 rig 'only' pulls 574W under load - both supplies' fans spin at acceptably low levels. You wouldn't hear them over and above the system's noise, and running both with a 500W load makes them near-silent, in our opinion.
Final thoughts
Stating an incredibly salient but overlooked point first, a 1kW PSU modulates its load to match the components. It'll provide 300W if that's all that's required, and it will do so with near-silent operation, too.
The advantage of a high-quality, high-capacity PSU is that it'll continue providing clean power as your component needs increase, right up to a tasty 1kW. It should also provide an eclectic range of connectors - primarily graphics-related - that scale with the introduction of more kit. Strong 12V lines are a must, of course, as is the ability to keep going in different environments. Think of it as future-proofing your PC, insofar as that's possible, really.
Thankfully, the price of 1kW power supplies has dropped significantly in 2008, and there's little need for all but the cooling-intensive users to look at higher, significantly costlier, capacities. At the very low-end of the 1kW pricing scale is the non-modular AKASA PowerMax 1000 V2, as reviewed here. Priced at £117, including VAT, a price more-commonly associated with 850W models, it's a no-nonsense supply that does exactly what it says on the cover. Efficiency is excellent, lines are strong, cable-runs are sleeved and long, and the price (worth repeating, we feel) is sharp.
However, retailing a 1,000W PSU at that level intimates some kind of sacrifice. We'd like to see a larger range of PEG connectors, which, after all, are one of the selling points of a high-end PSU: a 1,000W model needs to be able to run three-way SLI right off the bat, without using additional connectors. Further, we'd like to see a bit more current on both 12V lines, too, and the power output rated at 50°C, but the attractive street price makes up for most of the foibles. Perfect? No, not at all, but worthy of a shortlist if your budget is tight and power's a priority.
The Corsair HX1000W is a different kind of beast. Priced at around £30 more (£146), it's a modular 1,200W PSU in disguise. Guaranteeing a continuous 1kW at 50°C, more cables than you can shake a stick at, and, with plenty of beef on the 12V lines, three-way SLI certification in the bag, its credentials are above average. Efficiency, too, is superb, and the under-load lines very strong.
Corsair will despatch modular 6+2 PEG connectors, should users want them in lieu of the 6-pin PEGs shipping with our sample, we were informed. All told, we reckon the extra £30 spent on the HX1000W is worth it: the warranty is better, the additional connectors serve a genuinely useful purpose, and the up to 50°C rating is a boon, hinting that there's more under the hood.
Bottom line: two good, relatively inexpensive 1kW PSUs that do exactly as promised. We'd opt for the better feature-set of the Corsair, although the AKASA can just about be recommended to users on a budget - well, you would be if purchasing kit that can draw near-1,000W, wouldn't you?
HEXUS Awards
Corsair HX1000W
AKASA PowerMax 1000 V2
HEXUS Where2Buy
The Corsair HX1000W is currently on pre-order at SCAN for £146.88
The AKASA PowerMax 1000 V2 is currently available at SCAN for £117.49
HEXUS Right2Reply
At HEXUS, we invite the companies whose products we test to comment on our articles. If any company representatives for the products reviewed choose to respond, we'll publish their commentary here verbatim.
Official response from Howard Bateman, Technical Director, Akasa Europe Ltd, dated April 21st 2008 and published as part of HEXUS' right2reply policy:
Good evening everyone
Akasa would like to thank the gang at HEXUS for the review opportunity and appreciate your renowned integrity.
I am sorry for any confusion relating to the continuous wattage rating the continuous 1K output is rated at 50◦C, this is printed on the box output spec.
There was a typo on our product spec sheet. The 30◦C relates to ambient working temperature, in other words, the temperature. of the working environment.
It is true that this 1KWatt model cannot run 4 x GeForce 9800GX2 or even three – but when we embarked on this project the information gain from the two principle
Vendors was analysed so we aimed to meet the 80% of the general requirement and we do realise that even we cannot be everything to everybody.
So our humble goal was set - to be affordable with no-nonsense approach and fit in most chassis and support most popular gaming requirements
Both PCIe legacy and support the new V2 product coming thru and uphold the Akasa values of good reliable, quality product and value for money without
Any compromises been introduced like any negative factors for examples batch failures etc. Our RMA target is set to achieve below 0.5%on total RMA .
So it decided that we have 2 x 8 (6+2) and 2 x 6pin but to use “higher quality with lower copper loss ” conductor cable to ensure the voltage drop at the termination (GPU end)
Is minimised when under full load demands, Of also to support the typical new design demands card requirements of 8pin and 6pin .
So it could run 4 x legacy mode GeForce 9600 GT / 4x ATI 3870 using 4 x 6pin or support the new twin dual GPU card 2x 9800x2 /x2 3870x2 .We have not adopted a modular approach to cabling to this project, Our no-nonsense design with fixed cables means there is no power loss or leakage across
The extra set of connectors connections that modular design have.
The Achilles heel of most modular & semi modular designs is that inadequate cable retention support , this extra feature isnot deployed due to cost and real estate that compromises
The design and also extendise use of normal plastic connectors can lead to breaking easily when physical load is applied to cables during routing or tying in.It is generally accepted that in power deliverance is the less connections possible are preferable especial high current bearing cables for the motherboard and PCIe .
There is a little typo on the result page of your review in regards to the Corsair product - the 5V & 3.3V current rating are incorrect.
From my point of view to run triple Nvidia GPU offerings a 1200W would be more suitable for all out gaming (over clocked environment) and we do have a product
To meet this exacting demand that we will offer HEXUS to openly test and will be on sell during May .
This is product is focus and targeted to fully support the Intel Extreme boards with high power demands of been able to be fully over clocked .Best regards
Howard
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