Here is one comparison:
http://www.xbitlabs.com/articles/cpu/di ... html#sect1

I see that idle power consumption between Athlon II X4 640 and Phenom II 955 differs 5 W.
This is not so much difference and price is almost the same so I am thinking of upgrading my file server with one of these and the 955 looks good.

But here is another comparison:
http://www.servethehome.com/amd-phenom- ... based-whs/ 57W idle with pico-psu
http://www.servethehome.com/amd-athlon- ... pu-review/ 41 W idle with pico-psu

So how come Xbitlabs measure only 5 W difference but servethehome measures 16 W difference? I see many reviews with different results of idle power consumption.

I can get the 955 for a slightly higher price than the 640 so performance for the money seems better with the 955. But my file server will mostly be idle and I do not want much higher electricity bill and if the difference is 16W then I think I would get the 640. If the difference is only 5 W then I would like the 955.

Here wee se only 5W difference between X6 1055T and X4 640: http://www.legitreviews.com/article/1481/13/

Here is only 5 W difference between Athlon II X4 635 and Phenom II X4 965 BE:
http://www.hexus.net/content/item.php?item=26122&page=6

So I can count on a difference of about 5 W between the 640 and the 955 at idle then?

I'm getting 39.5W at idle with Phenom II 965 and ATX seasonic X-650

Second post with photo here:

viewtopic.php?f=28&t=60616

Both of them are way overkill for a file server if you ask me.

They don't measure the power consumption of the CPU, they measure the power consumption of the whole system.

servethehome used a Gigabyte 880G based mainboard and a Pico-PSU for the Athlon X4, but an MSI 890GX based mainboard and a 550w PSU for the Phenom II (see paragraph "Power Consumption").

Yes the performance as file server is fine with my 4850e CPU.
I am a little bit "torn between two hay taps" or what they say.
It is nice to make use of my low power 4850e CPU, it works withot problems for most tasks, but a little bit slow at video compression.
The Athlon II 640 is a cheap upgrade and the Phenom II 955 is just a little bit more expensive.

I use FreeBSD as operating system. When installing software from ports it compiles the software from source code.
This can sometimes "take forever" to complete with my 4850e.

also dependson which stepping 955 is in that xbit labs review.


most 955s in reviews are probably C2 stepping which didnt have c1E. C3 955s do have it. so they idle even less.

I use Linux too, my rig (in link above) idles at 59-60W versus 39w for my Win2000/XP. Power consumption comes down to the drivers , not so much the hardware. I'd go for the quad Phenom II C3 and undervolt if necessary. Adobe Flash on 64-bit Linux is basically malware, it loads CPU 80-90% running full-screen youtube video!

Yes, it's "about" 5W. Speaking of idle/load energy efficiency, 610E & 615E are very good if you can find them. If you are concerned about idle power consumption and don't want to spend a fortune, just get a C3 Athlon X2. Motherboard choice is equally as important. You may save 5W here and lose 10W there.

Option B, wait out a couple of months to see next-gen AMD tech. Power consumption is going to get better.

Thanks for all your input here! I think I will skip this upgrade now.
I will save the money for a larger upgrade in the future.