power saving processor

[liquidpaper007]

hi
im looking for cpu that takes very little power and is able to go into a desktop motherboard.

any suggestions?

 

[pat]

hi
im looking for cpu that takes very little power and is able to go into a desktop motherboard.

any suggestions?

well.. which motherboard? AMD64 CPU take very little power compared to Intel prescott CPU...

 

[danizaken2]

The new athlon 64 cores: venice, san diego.
or athlon 64 x2 which are all new cores, if your going dual core.

 

[o1die]

The amd turion runs as low as 25 watts at around 1.0 volts. It's available at several venders, including newegg and ewiz. But you need a socket 754 board with voltage adjustments, such as the dfi nforce3 or nforce4. Nforce4 is actually cheaper, if you use pci-e video. The Lancaster core is the latest socket 754 in mobile form. You also need a special heatsink to use turion's, and most people will remove the standard amd heatsink bracket and mount one of the custom plates that come with premium heatsinks. Socket 939 semprons should be available soon, and will be much cheaper and use less energy than regular 939's. Any of the amd cpus run at lower voltage using the "cool and quiet" software, but the software doesn't work on all boards. I have 2 amd boards, and cool and quiet only works on one of them.

 

[Crashman]

The Athlon64 3200+ is clocked at the same speed as the Pentium-M 755, gives about the same performance (better in some applications), and draws only a few more watts.

 

[ltcommander_data]

It depends on what the intended use of your computer is.

For example, if you want to have the absolute lowest power consumption, you could get the Pentium M Dothan with a 400MHz FSB. If you want more performance but still low power you could get a Dothan with a 533MHz FSB. In general, Pentium Ms are great for small form factor PCs, and especially media centre ones for the living room. Pentium Ms are becoming more popular in the desktop market thanks to AOpen who have been building motherboards for them. As such these notebook chips are easier to use on the desktop. o1die describes the lengths you need to go to to get an AMD Turion onto desktop such as special heatsinks. AOpen generally include heatsinks with their Pentium M motherboards. The Dothan, especially the higher models offer good performance in most applications and games, but are weak on media encoding.

If you want to save money, you can follow Crashman's advice and get a lower end AMD64. They are definitely cheaper, and can offer better performance depending on the model your comparing to. While they generally only use a little bit more power when idle, their power consumption at full load is more than double. To avoid being yelled at by AMD supporters, I'll reiterate you can get a lot more performance for the same price by going with an AMD64 instead of a Dothan. It depends on how badly you need to keep power consumption down.

If you are concerned about power you should also carefully pick your components. High end graphics cards can quickly use so much power that your choice of processor is irrelevent. Something like the nVidia 6600 offers great performance while having low power compsumption.

Power comsumption can also affect your motherboard choices. For instance, since the Pentium M is a mobile processor, AOpen offers mobile motherboards to go with them. These motherboards offer lower power consumption compared to their desktop counterparts. The 915GM (M for mobile) also offers integrated graphics. If you aren't planning to play many games this could be a great option since the graphics barely increase power usage. Of course, going with mobile products like the 915GM and the Pentium M increases cost.

These two articles offer some power comparisons:
http://www.tomshardware.com/howto/20050621/37watt-pc-16.html
http://www.xbitlabs.com/articles/cpu/display/pentiumm-780_9.html

A good spread of performance comparisons is here:
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2382&p=10

 

[Crashman]

While they generally only use a little bit more power when idle, their power consumption at full load is more than double.

COMPLETELY WRONG, unless you take THG as gospel. For one thing, Tom's never compared a Venice to a Dothan, they used an older CPU instead. And for another, AMD and Intel calculated their max power numbers differently. I've read several articles showing the A64 3200+ Venice running 27W under peak load, and the Dothan 755 running 21W under peak load. That difference, 6w, is about as much as a nightlight bulb.

BTW, I use a Northwood in my own system, simply because it would be too much hassel to swap out any major components. I have a 3200+ Venice here I use for benchmarking.

And the GeForce 6150 chipset is a great choice for running a cool Venice system, because of its excellent performance and ability to run passively cooled. Read the temps of my latest HTPC chassis review at SysOpt.

Overall, the desktop boards for Dothan are lacking compared to those for Athlon 64's, and cost twice as much. The Dothan CPU is nice, but at 2x the price of an equal or better Venice...which only consumes very few more watts, building a Dothan system is a waste of very much money.

 

[ltcommander_data]

Somehow I knew mentioning an Intel processor would get people riled up.

Even if THG shouldn't be believed, that's why I included the article from X-bit Labs. That one clearly shows a Dothan 2.26GHz producing 27W as rated under Burn Load, while a 2.4GHz Venice produces 59.6W. Granted the Venice is clocked slightly higher but that doesn't account for the 2.2 times increase in power consumption. For interest, the Dothan consumption when idle is 14W while the Venice is 16.8W. Its a 20% increase, but at such small numbers its irrelevent.


I don't want to get into a full blown argument since it would be of little help to liquidpaper007.

In any case my position is the same. If power consumption or perhaps very small form factor is critical and cost isn't as important then the Pentium M is an option. Otherwise a lower clocked AMD64 with a Venice core would do nicely.

 

[Crashman]

Something funny happens when both the Venice and Dothan get around 2.4GHz, they start acting more like traditional desktop processors, making big heat.

This is actually something overclockers are very familiar with. It's not at all odd to see a processor go from 35C to 37C with a 2.0GHz to 2.2GHz overclock, but then jump to around 45C or more when taken to 2.4GHz, using the same cooler.

My Venice goes around 2.45GHz before it starts creating heat faster than it can expel it. The power consumption curve for increasing clock speeds starts out low but accelerates very quickly.

 

[ltcommander_data]

I'll acquiesce to Crashman on this then. I'm not much of an overclocker myself and buy higher clocked processors to begin with. As such I haven't gone through one of those weird transition zones. I'll have to trust your opinion.

 

[Crashman]

It happens with stock speed processors too! It tends to be what limits what's available on the market.

 

[endyen]

Hey Crash, having that paranoid android call you on supprting Amd is too funny. How many times have you been called an Intel fanboy?

 

[shawnlizzle =]]

i would think pm is indeed on par or even better than a64s, the reason we arn't jumping on it is because of its limited platform

 

[Crashman]

I think the only guys who called me an Intel fanboy were AMD fanatics. Anyone who's reasonable and rational is the enemy of the dubya types (either with us or against us).

I used to put AMD processors on Intel chipsets, when that was no longer an option I went to ALi, but when ALi screwed up stability to gain a little performance I went to nVidia and SiS. The 735 rocked!

Oh, and I've built Intel systems too! I'm getting it from both sides!

Anyway, Dothan does have a low-power edge, but it's not as big as people think any more, and it comes at a horrible expense.

 

[ltcommander_data]

I was just looking through some benchmarks and I noticed a 2.26GHz Dothan overclocked to 2.75GHz. Despite the 21% increase in clock speed, the power usage only increased from 92W to 94W when idle and from 124W to 129W under full load. I wonder why the rapid thermal increase issue didn't occur here?

"Running at stock voltage levels and utilizing the AOpen retail cooler, we were able to overclock our 2.26 GHz Pentium-M processor to 2.75 GHz, an increase of 21%."

Granted this took place on a desktop platform, but I don't think AOpen's retail cooler could be that effective since its puny and only made of aluminum. In fact, they specifically say "AOpen's stock cooler is simply not a very effective heatsink."

Maybe, Dothans or the process they are produced in just aren't as prone to rapid thermal increases.

http://www.gamepc.com/labs/view_content.asp?id=pm780&page=3

 

[Crashman]

It's possible that the particular CPU they're using simply had higher clock speed tolerance. There were users who got their PIII's up to 1.2GHz while most wouldn't go over 980MHz in the early days.

 

[ltcommander_data]

I believe the article also spectulates it could be process improvements that Intel's making as time goes on.

I guess its good to get lucky.

 

[Crashman]

I've seen that too, even with the PIII.

 

[endyen]

That does look promising. Where can we see those benchies?
Oh there!!
Now if only Intel can pull off a seamless transition to desktop.
Wether the handpicked benches will continue to hold up then, is another question.

 

[ltcommander_data]

The benchmarks of the 2.26GHz Dothan overclocked to 2.75GHz on stock voltage and cooler are here:

http://www.gamepc.com/labs/view_content.asp?id=pm780&page=6

The benchmarks on the above page are for games. Through the later pages they go through 3D rendering, content creation, and media encoding.

The original link for the power comsumption charts is in an earlier post.

I hope that's what you are looking for.

 

[mpasternak]

Any AMD chip will do the job. they use a safe ammmount of power, produce little heat, and provide the "cool and quiet" feature which will lower the clock speeds and power consumption when idle