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Corsair outlines Haswell PSU compatibility

Corsair outlines Haswell PSU compatibility

Corsair has stated that most of its PSUs utilise DC to DC technology and should be compatible with Intel's new Haswell CPUs

Corsair has outlined compatibility between its PSUs and Intel’s forthcoming Haswell CPUs. It's statement follows recent concerns over new sleep states introduced with its new CPUs. We recently reported that Haswell’s new sleep states, C6 and C7, can potentially drop the power consumption to just a tenth of that of Ivy Bridge CPUs.

This is great news for laptop battery life, and we’re certainly not against better power efficiency in PCs either. However, this low voltage could be a problem for current PSUs; at the very least there may be issues coming out of sleep, with Corsair stating that some PSUs - not just its own, use technology that could require a complete reboot, while other reports we’ve seen go as far as saying memory content corruption could also arise.

Thankfully, the vast majority of its current range appear to be future-proof, although as Corsair might be hinting at in its statement, the issue begs the question about whether Intel's R&D department was unaware of the issue or just keeping quiet, with responses from PSU manufacturers so far rather knee-jerk affairs. Referring to Intel's presentation at IDF, Corsair’s statement reads as follows:

Even if the sleeping CPU is the only load on the +12V rail, most power supplies can handle a load this low. The potential problem comes up when 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 we are still working with Intel on the details of the testing methodology they use 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 is most of their 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. So whatever your budget, if you choose Intel's new Haswell processor and wish to utilize the new, low power C7 sleep state, Corsair has a power supply for you.


You can see the full statement as well as a complete list of Corsair’s Haswell-compatible PSUs and those it's currently checking here. Are you concerned about your PSU being compatible with Haswell's new sleep states? Let us know in the forum.

20 Comments

Discuss in the forums Reply
ZeDestructor 10th May 2013, 02:27 Quote
When the first manufacturer responses started coming out, it was fairly obvious that most DC-DC based PSUs would be compatible. To me at least. Since only one massive 12V rail is loaded rather than a bunch of small rails that trigger weird regulation crosstalk, interference and whatnot...
jonnyGURU 10th May 2013, 02:35 Quote
Well, that was quick! :-p

(Posting this as news, that is. Seeing how the blog post just went live an hour ago.)
Aracos 10th May 2013, 02:37 Quote
Have power supply manufacturers found that there isn't much need for new power supplies anymore with low cost products now being very quiet, stable and reliable? Is this a coordinated scare story to cause knee-jerk reactions which will push power supply sales?

I'm not usually one for a conspiracy theory but this is all a little fishy.
jonnyGURU 10th May 2013, 02:42 Quote
Quote:
Originally Posted by Aracos
Have power supply manufacturers found that there isn't much need for new power supplies anymore with low cost products now being very quiet, stable and reliable? Is this a coordinated scare story to cause knee-jerk reactions which will push power supply sales?

I'm not usually one for a conspiracy theory but this is all a little fishy.

You apparently are one for conspiracy theories. ;)

It was Intel that started this. Not the PSU companies. And if you read the post, it says that most PSU's will already work, which would mean for most people that already have a quality power supply that they do NOT need to run out and buy a new PSU.
SchizoFrog 10th May 2013, 02:45 Quote
Quote:
Originally Posted by Aracos
Have power supply manufacturers found that there isn't much need for new power supplies anymore with low cost products now being very quiet, stable and reliable? Is this a coordinated scare story to cause knee-jerk reactions which will push power supply sales?

I'm not usually one for a conspiracy theory but this is all a little fishy.

Not at all... You can easily get older PSU's and test them. Feel free to also use a PSU that is not certified as compatible with your new Haswell CPU... It's your money after all.
Aracos 10th May 2013, 02:49 Quote
Quote:
Originally Posted by jonnyGURU
Quote:
Originally Posted by Aracos
Have power supply manufacturers found that there isn't much need for new power supplies anymore with low cost products now being very quiet, stable and reliable? Is this a coordinated scare story to cause knee-jerk reactions which will push power supply sales?

I'm not usually one for a conspiracy theory but this is all a little fishy.

You apparently are one for conspiracy theories. ;)

It was Intel that started this. Not the PSU companies. And if you read the post, it says that most PSU's will already work, which would mean for most people that already have a quality power supply that they do NOT need to run out and buy a new PSU.

But the idea has been planted in peoples heads. The sheer idea of something possibly not working with future upgrades is enough to send some people buying new products. Corsairs statement was definitely informative but they also know that if they're one of the first companies to state that their power supplies will work then there will be those who will buy their power supplies to be safe. Don't get me wrong Corsair aren't a bad manufacturer, neither are Enermax but there's definitely a hint of capitalising on a possible compatibility issue going on, especially when the stories get so much press :-)
fluxtatic 10th May 2013, 07:45 Quote
Correct me if I'm wrong, but this is only an issue if you sleep your PC, right? I don't know that many people that do - seems most either shut down every night, or leave it running 24/7. I used to try sleep here and there, but it never seemed to work right and I had to reboot anyway.
SchizoFrog 10th May 2013, 08:00 Quote
Fluxtatic... I agree with you. Sleep mode has nearly always caused issues when trying to wake. However, I recently decided to try the Hibernate option instead and that works perfectly. I can now use my MCE remote to send my machine in to Hibernate state (which looks the same as powered off) and then wake it again with the remote. I think this state would also cause issues with the Haswell CPUs.
Combatus 10th May 2013, 09:34 Quote
Quote:
Originally Posted by jonnyGURU
Well, that was quick! :-p

(Posting this as news, that is. Seeing how the blog post just went live an hour ago.)

:D We don't muck about!
edzieba 10th May 2013, 10:47 Quote
Quote:
Originally Posted by fluxtatic
Correct me if I'm wrong, but this is only an issue if you sleep your PC, right?
Further, it;s only an issue if you sleep AND use the new power states. Turn the new power states off (or run a BIOS/UEFI that does not support them), and the power usage will remain around - or slightly lower than - existing Ivy Bridge CPUs; i.e. no issues with current PSUs.

You could upgrade your PSU in order to use the new power states, but the savings (~10w to ~0.1w) are so small you'd never recoup your 'investment' in reduced electricity cost.
loftie 10th May 2013, 10:58 Quote
I think corsair may need to make their list a bit clearer, or provide more information. As an example I own a TX750. There are 2 such TX750s - and that doesn't include the V2. Does this mean they all work? Considering that, iirc, I bought it pre lynnfield.
faugusztin 10th May 2013, 12:01 Quote
Quote:
Originally Posted by fluxtatic
Correct me if I'm wrong, but this is only an issue if you sleep your PC, right? I don't know that many people that do - seems most either shut down every night, or leave it running 24/7. I used to try sleep here and there, but it never seemed to work right and I had to reboot anyway.
Quote:
Originally Posted by SchizoFrog
Fluxtatic... I agree with you. Sleep mode has nearly always caused issues when trying to wake. However, I recently decided to try the Hibernate option instead and that works perfectly. I can now use my MCE remote to send my machine in to Hibernate state (which looks the same as powered off) and then wake it again with the remote. I think this state would also cause issues with the Haswell CPUs.

No, you are incorrect. Since Nehalem Intel CPU has per core C-states. That means that while one core is in C6 or C7 state, other core is fully working; this is actually part of the Turbo feature set as well - put one, two or three cores in C6 state, while the one remaining runs at full Turbo clock.

And considering this slide, i am pretty sure they are talking about per core C7 state when the system is running and all cores enter C7 state :
http://www.tomshardware.com/gallery/c7jpg,0101-382656-0-2-3-1-jpg-.html
Note the "even when display is active" line.
Pranja 10th May 2013, 12:25 Quote
Any PSU will work if C6 and C7 are turned off.
jonnyGURU 10th May 2013, 14:13 Quote
Quote:
Originally Posted by loftie
I think corsair may need to make their list a bit clearer, or provide more information. As an example I own a TX750. There are 2 such TX750s - and that doesn't include the V2. Does this mean they all work? Considering that, iirc, I bought it pre lynnfield.

Yes. That means they all work... for the same reason. They use DC to DC for the non-primary rails.
Salty Wagyu 10th May 2013, 14:35 Quote
What about the first HX 750? (bought it around when the first Intel i5 came out) The site says it's compatible, but the HX 750 they show on product page is different from the CMPSU-750HXUK I have - which is discontinued on many shopping sites.
faugusztin 10th May 2013, 18:00 Quote
FYI Seasonic Rep statement :
http://www.overclock.net/t/1264890/official-seasonic-platinum-series-owners-club/530#post_19888932
Quote:
Sorry we have not updated our website for this information.

The following series from Seasonic are Haswell compatible.
P, X, FL, G
M12II-650, 750, 850
jonnyGURU 10th May 2013, 18:10 Quote
Quote:
Originally Posted by Salty Wagyu
What about the first HX 750? (bought it around when the first Intel i5 came out) The site says it's compatible, but the HX 750 they show on product page is different from the CMPSU-750HXUK I have - which is discontinued on many shopping sites.

And it's compatible... again... for the same reason.
VaLkyR-Assassin 10th May 2013, 23:09 Quote
I use sleep mode alot, never had any issues with it tbh. Not sure why others would have any unless there is a weakness in their hardware (i.e. failing components).
runadumb 11th May 2013, 11:07 Quote
Looks like my HX 850 is compatible even though its around 3 years old. I don't think I care that much but its nice to know it will work if needed.
I do plan on upgrading my original i7 920 to Haswell but I rarely use sleep mode.
faugusztin 11th May 2013, 11:30 Quote
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