Low Voltage cpus

[perdomot]

Starting to get serious on making an NAS for video files and want to figure out which cpus have the lowest voltages so I can save some money. I know about the Atom attached to the intel mobo but I want to get the cpu separate from the mobo. I plan on using the Speedstep/Cool & Quiet features to lower temp/volt even more but which company has the better implementation? Thanks.

 

[Acanthus]

An old pentium 2 PC?

If youre talking new only, you can undervolt E5200s pretty far before they get unstable.

 

[perdomot]

Well I would like something more modern LOL. Trying to decide between an 35W Celeron 430 or a Sempron LE 1250 so far.

 

[eelw]

When I swapped out my B0 Q6600 for a G0, I was amazed at the temperature difference. So decided to play around with undervolting. Got it down to 0.95v. With my ThermalTake V1, I could run it passive at only 50C full load. Yeah, still using much more power than an Atom though.

 

[taltamir]

an atom is, bar none, the lowest power consumption cpu on the market.

 

[Flipped Gazelle]

Via Nano u2x00 series, lowest power consumption cpu on the market.

 

[SickBeast]

I think that so long as you can lower your voltage in the bios, any modern CPU should be fine for what you're trying to do.

I would personally go with the cheapest mini-atx/cpu combo I could find, then run it passive. Make sure you get a board with an integrated GPU.

 

[Binky]

I'd be looking at the VIA stuff. They're dirt cheap and use an absurdly low amount of power. You don't need much processor power for a NAS.

 

[perdomot]

Originally posted by: Binky
I'd be looking at the VIA stuff. They're dirt cheap and use an absurdly low amount of power. You don't need much processor power for a NAS.

I remember seeing a sub 60 watt pc build using via's pc3500 but I've never seen it on sale in the US.

 

[Binky]

You might start looking here: http://www.mini-box.com/site/index.html

They have a selection of mini-itx boards and cases. They also carry the very cool little pico-PSU.

 

[Zap]

Originally posted by: perdomot
Trying to decide between an 35W Celeron 430 or a Sempron LE 1250 so far.

I don't think the Celeron has EIST support, and not all Semprons have Cool & Quiet.

Originally posted by: Acanthus
If youre talking new only, you can undervolt E5200s pretty far before they get unstable.

I had one of my E5200 chips running set at 0.800v in BIOS on a Gigabyte G31 chipset mATX board. Using onboard video and with three 7200RPM hard drives, system idled at around 66W.

The E5200 is a good candidate for low power usage because it supports EIST and is the lowest end 45nm CPU not already soldered onto a motherboard.

For a low power computer you have to consider everything that goes into it, not just the CPU. Every additional hard drive adds power requirements, so go for the largest drives so that you can use fewer. This means the Western Digital 2TB, which also happens to be one of their "Green" models. Every additional fan adds power (fans can take several watts) so run everything passive if possible, with one system fan for ventilation. Power supply efficiency generally drops off below 20% output, so that 80% efficient 1000W power supply may only be 50% efficient powering an 80W system. With such low power draw the most efficient power supply you can use would probably be a Pico PSU from mini-box (Binky linked the site). Their 90W unit can probably power an undervolted E5200 plus several of those "Green" hard drives.

 

[Viditor]

Take a look at the new Yukon platform for AMD's Neo chips...
Gigabyte ITX boards

The Neo supports 64bit, TDP of 2.4w, and supports 1080P.
For HTPC, it's pretty much top of the rank it appears at the moment. The Atom on the other hand is better for Netbooks because it's lower power, and Netbooks don't display high end video files or run 64 bit apps...

 

[hans007]

if you look on ebay, some people are selling the 2650e chips from their emachines / acer laptops. i saw one in fs/ft forum here for $18.

15 watt tdp max.

 

[perdomot]

Originally posted by: Binky
You might start looking here: http://www.mini-box.com/site/index.html

They have a selection of mini-itx boards and cases. They also carry the very cool little pico-PSU.

Thanks for the link. Didn't know about these guys.

 

[perdomot]

Originally posted by: Zap

Originally posted by: perdomot
Trying to decide between an 35W Celeron 430 or a Sempron LE 1250 so far.

I don't think the Celeron has EIST support, and not all Semprons have Cool & Quiet.

Originally posted by: Acanthus
If youre talking new only, you can undervolt E5200s pretty far before they get unstable.

I had one of my E5200 chips running set at 0.800v in BIOS on a Gigabyte G31 chipset mATX board. Using onboard video and with three 7200RPM hard drives, system idled at around 66W.

The E5200 is a good candidate for low power usage because it supports EIST and is the lowest end 45nm CPU not already soldered onto a motherboard.

For a low power computer you have to consider everything that goes into it, not just the CPU. Every additional hard drive adds power requirements, so go for the largest drives so that you can use fewer. This means the Western Digital 2TB, which also happens to be one of their "Green" models. Every additional fan adds power (fans can take several watts) so run everything passive if possible, with one system fan for ventilation. Power supply efficiency generally drops off below 20% output, so that 80% efficient 1000W power supply may only be 50% efficient powering an 80W system. With such low power draw the most efficient power supply you can use would probably be a Pico PSU from mini-box (Binky linked the site). Their 90W unit can probably power an undervolted E5200 plus several of those "Green" hard drives.

Thanks for the suggestion on the E5200. I caught up on the sub 60watt pc video and they do mention the other parts play a role in keeping power requirements down so I'll be factoring that in too.