Lowest power dual-core

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smilingcrow
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Post by smilingcrow » Sun Apr 27, 2008 11:47 am

frank2003 wrote:However, there's a class of machines where running at the lowest possible power at idle (or near idle) is important - machines such as PVR and home file servers that are on 24/7. For these machines a watt saved is 24 watt-hours saved per day.
By PVR I assume you mean a HTPC which ideally should put itself in standby when it’s not recording or being used as that saves a lot more energy than shaving a few watts at idle. Ideally you can use all the power saving methods at your disposal.

scdr
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Post by scdr » Sun Apr 27, 2008 9:40 pm

frank2003 wrote:
However, there's a class of machines where running at the lowest possible power at idle (or near idle) is important - machines such as PVR and home file servers that are on 24/7. For these machines a watt saved is 24 watt-hours saved per day.
Even better - get a machine that will reliably start up from standby/hibernate, and set it up to shut itself off when not in use. PVRs can turn themselves on from timer. File servers from wake on lan.

(Cuts non-use power to a few watts.) Get a power supply that is efficient at standby, and a motherboard that has low power draw on standby, and turn off any wakeup features you aren't using, and you can cut it even further.
(e.g. http://www.lesswatts.org/tips/ )

frank2003
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Post by frank2003 » Mon Apr 28, 2008 3:07 pm

scdr wrote: Even better - get a machine that will reliably start up from standby/hibernate, and set it up to shut itself off when not in use. PVRs can turn themselves on from timer. File servers from wake on lan.
The last time I tried this I almost got a divorce from my better half when the PVR did not wake up from sleep to record American Idol :-).

C'mon folks, we've been working with computers for long enough. How many of us can honestly say our PC can wake up reliable from standby, every time?

I worked with many PCs in my lifetime, I have yet to see a single PC (notebooks included, for those who wanted to argument the point that standby operation is really intended for notebooks) that can wake up without fail.

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Post by smilingcrow » Tue Apr 29, 2008 1:19 am

frank2003 wrote:The last time I tried this I almost got a divorce from my better half when the PVR did not wake up from sleep to record American Idol :-).
C'mon folks, we've been working with computers for long enough. How many of us can honestly say our PC can wake up reliable from standby, every time?
I worked with many PCs in my lifetime, I have yet to see a single PC (notebooks included, for those who wanted to argument the point that standby operation is really intended for notebooks) that can wake up without fail.
Mine’s about 99.x% reliable which is almost as good as my stand-alone hardware PVR. For those odd shows that are missed they will either be repeated, non essential or available via P2P. How many TV shows are you really going to be that bothered about missing?

astrayan
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Post by astrayan » Wed Apr 30, 2008 6:54 pm

smilingcrow wrote:Under-volting is not a mainstream hobby and reviews focus on what you can achieve at stock settings
But congratulating a manufacturer on efficiency implies that all manufacturers overvolt their chips by the same margin. They might. It might be a special law in USA somewhere that says there must be a 0.2V margin. The reviewers don't go into that.
smilingcrow wrote:With regard to under-volting as low as 0.8V, from what I’ve seen it seems to be the law of diminishing returns. How much do you save at idle when dropping VCore from 1V to 0.8V?
I looked at that last night on my M2-ATX, measuring DC current and votage to 0.5%.

The Venice core runs at 1.1V (min) and this costs 2.6W at idle, but more when being intensively used. It's about .48W per .025V increment. 2.6W might not seem like much, but it's near 8% total.

I tested this: A8N-VM-CSM, Winchester A64 @ 0.875V, Seagate 320GB, 512MB DDR. It took 32.5W @ 96% efficiency (31.2W).

I also tested : A8V, Venice A64 3500 @1.1V, 9600XT AGP, 512MB DDR, Maxtor 160GB, and that mysteriously took 35.5W

borax
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Efficient home server?

Post by borax » Thu May 01, 2008 7:53 am

Borrowing the thread a bit. I'm currently looking at building a file/web server that will be up n running 24/7. Right now I'm trying to figure out what CPU / mobo I should go with. Low W at idle is on the prio list. I have 5 drives that I will use (WD GP), that will spin down when not used. Just mentioning this as that affects which PSU / mobo that I could use for this purpose.

The X2 4050e (or 4850e) with a 780g mobo would most probably suite my needs as that combo seems to have quite low power demands. The E2160 also seems quite nice but I think it's hard to find good mobo's for the Intels. The least power demanding as far as I've been able to find on the web seems to be the G33's based. Does anyone know how the 45nm E7200 compares in power demands to an E2160? I know this is a very unfair comparison as for example the E7200 is faster but if I could get a faster CPU that use less W then I'm happy :-). So, any thoughts around a decent performing low power CPU / mobo combination for use in a "home server"? Yet again low idle power is what's interesting for me as it will be idle 95% of the time. Would be grateful for any responses.

Thanks
/ Ola

astrayan
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Post by astrayan » Thu May 01, 2008 7:13 pm

Something you should consider about the Greenpower drives, is that they appear to be at best SATA2, and have an undeclared spin rate, which will decrease data speed. SATA 2.5 may be needed for a staggered startup, so that you can use a small/efficient PSU. It's rumoured that the pins on a SATA drive can sometimes be used to specify staggering,... (i found some info on WD GreenPower)

All Western Digital Serial ATA hard drives come with PM2 (power management) disabled. This setting should be used for desktop/workstation computers. If you are using the drive in a RAID/enterprise environment, and wish to enable power management on the drive (controlled spinup via spinup command per ATA standard), place a jumper shunt on pins 3 and 4.



========= this is from a review of one of the Seagate drives

Staggered spin up is a feature that allows drives to come on in a sequence in order to avoid massive drains on the PSU. Imagine having five or more SATA drives in a single PC. When you start this PC, you would have a massive drain on the PSU’s 12v and 5v rails. This would cause even the most powerful PSU to struggle at start up.

Staggered spin up allows the drives to start up in channel order allowing drive on channel 1 to start, then channel 2 and so on until all drives are started. Staggered spin up is supported on SATA 2.5 boards. After all the drives spin up, the BIOS gets the queue to detect the HDD’s on the SATA channels and booting continues unhindered. This feature has been reserved to SCSI drives and not seen in the retail drive market until the now with SATA 2.5.

astrayan
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Post by astrayan » Sun May 04, 2008 3:41 pm

I have a result for the M2A-VM HDMI , Brisbane 5000+, 2GB, 320 Seagate SATA, powered by M2-ATX 12V DCDC psu.

Luckily, I was building this test system for my dad and his power criterion is not all that strict.

The board, due to the Asus/690G ATI chipset, is a miserable undervolter when controlled through RMClock from boot. Before the ATI drivers are installed, dynamic undervolting will crash the board if you step more than 0.1V, so single step transition mode has to be used. After the 180MB ATI drivers are installed, it's worse! You can barely use RMClock at all. It's quite difficult to finish off booting after RMClock switches in (pre-ATI driver). I only managed by using 9 p-states. After driver, you wouldn't bother.

However I did get some figures. 30.4W @ 0.8V. You could get that down another 4.5W, using less RAM and a Greenpower HDD. But the board really needs to be BIOS undervolted. The 5000+ would go 2.6GHz @ 1.1V, but you'd really need to use a 2GHz chip and undervolt it to 0.975V or something.

The 5000+ going full bore with iPrime, and WinRAR used 30W @ 1.1V

You get tears on the graphics output as this board changes voltage.

Can anybody tell me an AMD integrated board that can handle 0.8V->1.1V changes in RMClock without crashing?

AiZ
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Re: Efficient home server?

Post by AiZ » Mon May 05, 2008 11:09 pm

Hello,
borax wrote:Does anyone know how the 45nm E7200 compares in power demands to an E2160? I know this is a very unfair comparison as for example the E7200 is faster but if I could get a faster CPU that use less W then I'm happy :-).
It won't help you that much but... To give you an idea :
Image
Measured at ATX12V connector.
(Taken from http://www.hardware.fr/art/imprimer/717/)

Have a nice day,


AiZ

borax
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Re: Efficient home server?

Post by borax » Mon May 05, 2008 11:51 pm

AiZ wrote: It won't help you that much but... To give you an idea :
Image
Measured at ATX12V connector.
(Taken from http://www.hardware.fr/art/imprimer/717/)
Thanks! Gave me a bit more information, my French is not first class though. The E7200 looks quite promising for use in a low power system as it has very low idle (1,6W) and full power usage (20,8W). Then the next thing to figure out is what mobo / PSU to grab :).

yuu
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Post by yuu » Tue May 06, 2008 6:12 am

p45/g45 mch has 1.100v normal and undervoltable to 0.8v, amazing

both cpu/gmch running at 0.9V. i would like to see that

jaganath
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Post by jaganath » Tue May 06, 2008 7:04 am

The E7200 looks quite promising for use in a low power system as it has very low idle (1,6W) and full power usage (20,8W).
not so long ago <30W CPU consumption was only achievable with a mobile CPU. now, even a relatively inexpensive desktop chip can do this! Intel have really focused on performance per watt (and minimising power consumption in general) and the results are evident for all to see. for silencers this is indeed a Golden Age. :wink:

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