Haswell's C6/C7 low power states and PSU compatibility

PSUs: The source of DC power for all components in the PC & often a big noise source.

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zsl1010
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by zsl1010 » Fri Jun 07, 2013 5:40 pm

Matthew9226 wrote:I hope everyone now realizes that this is a non issue since Haswell is out now.
The S0ix isn't even enabled on these desktop SKU's.
Even though the new S0ix active idle states are not enabled, the old S3 sleep state is still there. According to Anandtech, the S3 state consume about the same power as the S0ix states.
In Haswell (and Clovertrail), Intel introduced a new S0ix active idle state (there are multiple active idle states, e.g. S0i1, S0i3). These states promise to deliver the same power consumption as S3 sleep, but with a quick enough wake up time to get back into full S0 should you need to do something with your device.
http://www.anandtech.com/show/6355/inte ... itecture/3

lb_felipe
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by lb_felipe » Sat Jun 08, 2013 7:02 am

Can we assume that Kingwin LZP-1000 is ready for Haswell?

Since it is a Super Flower rebadged...

http://www.super-flower.com.tw/news_det ... n=26&lang=
Last edited by lb_felipe on Sat Jun 08, 2013 7:48 am, edited 1 time in total.

CA_Steve
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by CA_Steve » Sat Jun 08, 2013 7:18 am

lb_felipe wrote:Can we assume that Kingwin LZP-1000 is ready for Hassweel?

Since it is a Super Flower rebadged...
I would.

Matthew9226
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by Matthew9226 » Sun Jun 09, 2013 6:51 am

zsl1010 wrote:
Matthew9226 wrote:I hope everyone now realizes that this is a non issue since Haswell is out now.
The S0ix isn't even enabled on these desktop SKU's.
Even though the new S0ix active idle states are not enabled, the old S3 sleep state is still there. According to Anandtech, the S3 state consume about the same power as the S0ix states.
In Haswell (and Clovertrail), Intel introduced a new S0ix active idle state (there are multiple active idle states, e.g. S0i1, S0i3). These states promise to deliver the same power consumption as S3 sleep, but with a quick enough wake up time to get back into full S0 should you need to do something with your device.
http://www.anandtech.com/show/6355/inte ... itecture/3
Mmm? Still a non issue.

CA_Steve
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by CA_Steve » Sun Jun 16, 2013 7:33 am

Legit Reviews sees 3W idle power improvement enabling C6/C7 on i7-4770K. .

QUIET!
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by QUIET! » Sun Jun 16, 2013 8:22 am

Nice results but it took a $250 PSU to get it.

It was an 860 watt 80+ platinum PSU but that just reinforces the fact that people don't need 860 watts for a PC that idles at 21 watts (and 80+ certification needs to start testing down there too).

Abula
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by Abula » Sun Jun 16, 2013 11:51 am

CA_Steve wrote:Legit Reviews sees 3W idle power improvement enabling C6/C7 on i7-4770K. .
And more impressive for us silent seekers,
Sure enough! By enabling 'Lowest CPU Idle Power Setting' in the BIOS the C6/C7 power states helped lower the CPU Core Temperature down to 34-36C with an average of 35C. This is a solid two degree Celsius temperature drop, which is rather impressive. Notice that the CPU Total TDP is now just 2W instead of 5W. This also coincides with the ~3 Watt performance difference that we noted at the wall.
This could mean lower rpms on the fans =)

CA_Steve
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by CA_Steve » Sun Jun 16, 2013 12:13 pm

QUIET! wrote:Nice results but it took a $250 PSU to get it.

It was an 860 watt 80+ platinum PSU but that just reinforces the fact that people don't need 860 watts for a PC that idles at 21 watts (and 80+ certification needs to start testing down there too).
Kinda misses the point. It wasn't the $250 PSU that caused the lower idle power. It's just what they opted to use for their test setup.

QUIET!
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by QUIET! » Sun Jun 16, 2013 6:01 pm

Its just odd that they would use a PSU so inappropriately rated when trying to go for low power consumption.

They are really lucky that the efficiency doesn't go to hell at 2.5% load. I know I wouldn't expect my PSU to be efficient at 2.5%, I keep my fingers crossed at 10%.

A lot of people will opt for an 800 watt 80+ (maybe bronze) PSU and it will be so inefficient at 3% load that the 3 watt savings will entirely disappear.

Very few people will buy a $250 PSU to get that 20-21 watt idle power and they didn't show a reasonable alternative or how to pick a reasonable alternative so if the point was saving power, they missed it and I stand by my previous statement.

CA_Steve
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by CA_Steve » Sun Jun 16, 2013 6:48 pm

It's more likely the reviewer has a standard test fixture that he uses for every build, from a simple IGP system to an SLI gaming system. This is the PSU he uses for it.

QUIET!
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by QUIET! » Sun Jun 16, 2013 9:16 pm

Sure but its not a smart setup for testing low power idle states.

A smart and inexpensive setup would be a picoPSU with a 12v brick wired for 12v current measurement.

If you wanted to do it right, 3-4 Agilent digital power supplies with GPIB or something for data aquisition.

If I ever get a picoPSU I will wire a brick for current and do some testing but it will be my low/mid-end hardware that I can find cheap...

Abula
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by Abula » Sun Jun 16, 2013 10:14 pm

QUIET! wrote:A smart and inexpensive setup would be a picoPSU with a 12v brick wired for 12v current measurement.
picoPSU arent that common on the market, my guess is more than 95% of the people that use desktops never have even heard of them. If they were to test with them, then people will complain that they didn't use a standard atx psu, 99% of the pc use standard psu, just not this super high end $200+ psu, still i feel its more correct to do it with that than with a picoPSU for practical purposes and for the audience that they are targeted.

I really don't care much about the haswell quads consumption, personally im going to peruse the c6/c7 power state for the 2C less temp, but i do think once the haswell dual core i3, pentium and celeron are release, we might see sites like SPCR and MissingRemote to put some setups that might use some picoPSU or alikes.

QUIET!
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by QUIET! » Sun Jun 16, 2013 10:55 pm

Of course a good review would explain what a picoPSU is and why it was used for testing. A very good review would probably test with a cheapo PSU and a flavor or two of 80+ rated PSU as well to show the effect of PSU choice on power usage.

The review in question hardly mentions the PSU, probably because they didn't want to mention that you really do need a good PSU to realize the power savings that the Haswell chip offers.

Its not all that hard to figure out so I have to conclude that the poor choices were intentional.

loimlo
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by loimlo » Mon Jun 17, 2013 7:37 am

Does PicoPsu support Haswell C6/C7 states? Just curious to make sure its existence.

QUIET!
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Re: Haswell's C6/C7 low power states and PSU compatibility

Post by QUIET! » Mon Jun 17, 2013 5:18 pm

I seem to recall that a PSU manufacturer remarked that all PSUs which generate 5v from the 12v rail would work and the picoPSU does exactly that, it generates everything from a single 12v brick.

Power bricks don't have any type of 5v turn on circuitry like a standard ATX PSU so it will regulate voltage with zero load and zero is less than Haswell minimum current needs.

I bet it works.

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