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Corsair, a leading provider of enthusiast-class PC components, on Friday published a list of power supply units (PSUs) compatible with the forthcoming Intel Core i-series “Haswell” microprocessors. Currently the company has over 20 PSUs that are guaranteed to be compatible with Intel Corp.’s next-gen chips and over 30 that are believed to support all the features of the new CPUs.

It recently transpired that Intel Haswell's C6/C7 power states require a minimum load of 0.05A on the 12V2 rail, whereas many desktop PSUs just cannot provide that low current. Numerous older PSUs, which comply with ATX12V v2.3 design guidelines that only called for a minimum load of 0.5A on the CPU power rail, can be equipped with a less sophisticated internal feedback loop/protection that cannot supply 0.05A to CPU. As a result, unless C6/C7 power states are disabled in the BIOS, PCs with older/cheap PSUs may become unstable when processors enter these states. To make the matters worse, many power supply units do not report minimum currents supported by 12V2 rail. As a result, it is now hard for system makers and end-users to determine whether their PSUs are Intel Core i-series “Haswell” compatible.

According to Corsair, the potential problem comes up when the CPU enters sleep mode, but there is still a substantial load on the power supply's non-primary rails (the +3.3V and +5V). If the load on these non-primary rails are above a certain threshold (which varies by PSU), the +12V can go out of spec (voltages greater than +12.6V). If the +12V is out of spec when the motherboard comes out of the sleep state, the PSU's protection may prevent the PSU from running and will cause the power supply to "latch off". This will require the user to cycle the power on their power supply using the power switch on the back of the unit.

While Corsair is still working with Intel on the details of the testing methodology the chipmaker uses to check PSUs for Haswell compatibility, it is already known that a power supply that uses DC to DC for the non-primary rails (the +3.3V and +5V) will not have an issue with the new low power sleep states. This is because a DC to DC buck converter is used to convert +12V to +3.3V and +5V. This means that no matter what load the CPU puts on the power supply, there will always be a load on the +12V because the +12V is required to provide power to +3.3V and +5V.

Corsair utilizes this DC to DC technology in most of its power supplies. Starting with the CX750 and CX750M and moving all of the way through the GS series, TX and TX-M series, the HX series, both the AX series Gold and AX series Platinum, and the new AXi Series. Basically, Corsair can provide a Haswell-compatible PSU at almost any budget.

The list looks as follows and was originally published at Corsair's web-site:

Tags: Corsair, Intel, Haswell, Core, 22nm, Shark Bay, Lynx Point


Comments currently: 27
Discussion started: 05/10/13 08:30:50 PM
Latest comment: 06/19/16 09:25:19 AM
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Since Corsair uses other companies to manufacture their PSUs which are often just rebadged units, they have limited control over the actual design and compatibility. We'll see how the stupidness that is Intel shakes out with Haswell and PSUs. This is another Intel FUBAR design that they didn't bother to think through before imposing on customers and suppliers.

The only reason Intel is using this absurd PSU requirement is to try and reduce power consumption in sleep states which is minute to begin with, so it's a waste of effort but good for marketing to the techniocally challenged who don't know any better.
3 1 [Posted by: beenthere  | Date: 05/10/13 08:30:50 PM]
- collapse thread

Yes, I think Corsair do rebranded Seasonic power supplies. In the current market and economic conditions, I think the Intel team must have been dreaming in a deep sleep state themselves, thinking they could push this one onto upgraders. Home goal.
2 1 [Posted by: linuxlowdown  | Date: 05/10/13 09:27:22 PM]
didn't they slightly change the design like modular/ non modular etc. so they have the same base design

by the way i am lucky that i took a lot of time deciding witch one i wanted and i bought the HX because of the high efficientie so now i know it will still be useful for the next 4 years.
1 0 [Posted by: massau  | Date: 05/11/13 03:44:02 AM]

Right now, only the AX is a rebadge. The rest of the product from CWT, Chicony and Flex is actually engineered by Corsair.
1 0 [Posted by: jonnyguru  | Date: 05/10/13 08:52:29 PM]

Would you guys like some cheese with that whine? Chances are desktop mobo manufacturers are just going to mod their bioses to not use those sleep states anyways, because the real benefit is for mobile users. I know I want a laptop that I can put in standby on Friday and resume on Monday with 99% battery left.
1 1 [Posted by: AnonymousGuy  | Date: 05/11/13 02:12:45 AM]
- collapse thread

But what are you going to do over the weekend after all the girls turn you down because you have a big Intel logo tat on your forearm within a love heart? You're never ever going to need S6 and S7. You need that Intel laptop at the ready with a half working Intel graphics driver that can handle HD video.
1 0 [Posted by: fanboyslayer  | Date: 05/13/13 07:41:18 AM]

Corsair doesn't engineer their PSUs, they contract other companies to produce price-point model PSUs. Corsair uses whatever supplier is low bidder for a particular design.

Any of the Seasonic models are top notch but the other brands sell a variety of PSUs that very from OK to good to a few excellent models. You can't tell what the quality is of the PSU unless you read PSU reviews from reputable sites that disclose who the actually PSU maker is. Other than the Seasonic brand, I would not trust any PSU supplier or brand without independent lab testing and inspection by a qualified, competent, objective independent third party.

As far as the Intel FUBAR, that's just typcial of Intel trying to ram their flawed designs down PC hardware suppliers throats. We saw how well BTX designs worked... The industry told Intel to stick BTX where the Sun don't shine. This PSU stupidness with C6/C7 states will disappear in the next iteration of Intel processors as it's unnecessary and undesirable.

C6/C7 states do not require the PSU issue that Intel has created and you aren't going to put a laptop in stgandby on Friday and have anything but an almost dead battery on Monday no matter what processor you use.

BTW, don't trust newbies to this forum with bogus user names intended to deceive. They are shills for other companies and you should be able to spot them and who they are shilling for by their name and the number of posts they have made to this forum.
1 1 [Posted by: beenthere  | Date: 05/11/13 11:23:46 AM]

til I saw the check 4 $5891, I have faith father in law woz like they say actualy taking home money in their spare time at there labtop.. there brothers friend had bean doing this for under eighteen months and resently cleared the mortgage on there condo and got a great new Chevrolet Corvette. I went here,
1 0 [Posted by: MelodyRamos41  | Date: 05/11/13 07:34:01 PM]

There's nothing wrong with the new Intel C6/C7 energy states. What was/is a problem, Intel didn't release the documents in advance time to allow power supply makers opportunity to produce compatible PSU's at the same time Haswell's were hitting the market. No fault to anyone but Intel and not necessarily a stupid design or flaw, just that no one was informed.

As it is, all the tree hugging green minded will not be happy that most folks will have to disable that in their BIOS until the time comes they market supporting Intel Haswell CPU C6/C7 Low Power State PSU's.

I'm all for operating a computer with less power, it only makes sense especially if you have 6 desktops going day and night not necessarily needing 100% CPU all the time.

There's no question about some of the many PSU makers out there. Those that sell 600W PSU for $29 are likely junk but I have had experience with many that continued to operate well into their 6th year or so. I personally don't use them but they are out there and they work while my systems usually get a Corsair, Antec, Roswell or Seasonic. All four are highly rated and have great warranty periods, not that I want to buy warranties.

Sure hope the C6/C7 power state PSU's get published and on the market soon, I'm ready to build a few socket 1150 systems.
0 0 [Posted by: gsuburban  | Date: 07/26/13 02:07:12 PM]

According to Intel's presentation at IDF, the new Haswell processors enter a sleep state called C7 that can drop processor power usage as low as 0.05A.
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0 0 [Posted by: Vignesh Waran  | Date: 05/12/16 01:57:03 PM]


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