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Lowest watt Core (non-Atom) CPU?

Last response: in CPUs
October 13, 2009 3:58:31 PM

I need a low power motherboard - but it needs to have more computing power than a single-core Atom. The system runs multiple Adobe Flex apps and is mostly solar powered with a high efficiency (digital) PSU. The power-hungry chipset packaged with the Atom processors combined with their low computing power seems to rule out the Atom - is there a Core Duo or Core 2 Duo CPU/chipset match that uses very little power? The Intel CPU guides that I have read do not help much when comparing chipset/CPU combos for max wattage....
a c 203 à CPUs
October 13, 2009 4:36:25 PM

What is the power budget you have to work with? "uses very little power" means different things to different people.
From your comments on the 'power-hungry chipset' of Atoms I'm guess it's VERY low power budget.
XbitLaps seems to think you could do a 50W C2D E3200 Celeron system for some pretty hefty performance needs.
From Xbitlabs review

Can you cannibalize one of the those Consumer Ultra-Low Voltage (CULV) laptop systems?
October 13, 2009 10:00:34 PM

Relative to their poor performance, the Atom systems seem to use a lot of power. Since Atom CPUs use very little...

The power draw of the motherboard, chipset, and cpu needs to be less than 40 watts. With drives that brings the budget up to 45-50 watts on a 60W digital power supply (the display is a separate power issue). I don't think I'll have access to any spares but the laptops I have are 65-85 watts which, although low, are not low enough. CULV systems that I've seen don't have that much of an advantage for the money and Core 2 Duo Mobile chips are $250-$350 if you can get them.

But thanks, a system with a e3200/e3300 seems like it could work. The X-bits Lab piece
( does say that a 50W system is possible with integrated graphics (which is what I'm using). But what confuses me is this - it lists the e3300 with a TDP of 65W. What does TDP really mean and then how can you get an idea about how much power a system will consume? How can you tell which is lower: the e2200, e3200/3300, or a e5200 if they're all rated 65 TDP?
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a c 203 à CPUs
October 13, 2009 10:59:44 PM

About the only reliable way is testing them yourself and maybe finding reviews on the web. The TDP is probably 'worst case' scenario. If XBitLabs was careful (and I think they are) you can see 65W TDP CPUs do vary in actual consumption.
Another review site that is interested in low power systems is SilentPC Review.
They ran mini-ITX MBs through a review using Core 2 E7200 and got 35W idle and 65W full CPU load for the entire system.
There are probably a few other articles on the SPCR site that would interest you.
If your applications aren't loading up the E3200 very heavily I think you'd have a chance of meeting your power budget.
October 13, 2009 11:39:24 PM

Remember that the Core CPU will also have a chipset which probably will suck up a fair amount of power itself (memory controller + IGP + etc); I know you've included that in the total power budget above, but it may well not be much less power-hungry than the crappy Atom chipset.

You could always try underclocking the Core CPU to reduce the maximum power consumption under load if you don't need all the processing power it can provide: it should still be faster than the Atom even if you underclock it below 1.6GHz.

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October 14, 2009 10:34:04 PM

take a look at the review I performed at silent PC reveiw. your best bet would be a pentium M and the 848 chipset
a c 203 à CPUs
October 14, 2009 10:40:09 PM

Can you still get socket 479 motherboards?
October 14, 2009 10:45:50 PM

TDP means nothing; its a thermal spec not a power spec. So a 95W TDP cpu can consume less in reality than a 65W TDP cpu. TDP is not even the maximum power the cpu can consume.

What matters is idle cpu consumption if your task involves desktop applications, which generally require alot of work to be done in a very short period of time, and they will idle afterwards. The idle time is generally very high, though it depends on your personal situation ofcourse.

The lowest consumption PC i have is a 4W idle AMD Geode LX system with 1GB RAM and 8GB flash storage. But that would not beat atom performance. So how much performance do you need from working with your applications?
a b à CPUs
October 15, 2009 12:04:49 AM

If you need plenty of computer power, soon-to-be-launched Athlon II X4 with 45w TDP will be a nice performer with low power. I think it'll have clocks up to 2.3 GHz.
October 22, 2009 5:33:35 PM

"... how much performance do you need from working with your applications?"

The application runs PostgreSQL and Apache with Adobe AIR as the frontend over three notebook drives(system+RAID). So it's the AIR app that I'm worried about because AIR/Flash/Flex seems to take a lot of CPU cycles for it to stay responsive to the user. I could use a more efficient server but WAPP is easy to configure....
a b à CPUs
October 23, 2009 1:52:55 AM

Athlon II X4 600e Quad Core 2.2GHz from AMD was just released, with an impressive TDP of 45w. The 2.3GHz version (45w) costs way more and the diff in performance should be negligible.
Newegg still doesn't list them, but I'd expect them to appear in the site by next week.
Prices were around $133 and $147 for the 2.2 and 2.3GHz versions. The price premium you pay is due to the fact that they are energy saving editions.
October 23, 2009 9:19:25 PM

Then what about the new Mac Mini? They have a good amount of speed andthe CPU has an impressive 25 TDP. I cannot find power usage specs but at $599 it might be a little expensive at 2.26Ghz but I could get behind it if the power usage was low.....