you simply do not know my situation. really, my "old server", who work now - pentium 3 - 866 mhz ( i think, in real performance it was close 1.6 ghz atom's)
is sometimes small too short for me. as time goeas, it get more and more worse. spam filtering is cpu eating task, as so as web servers on joomla and so on. in another case i not struggling, and live with my old server. a time ago i thinking to replace it with hardware who consumes less power - like as atom, itx all-in-one boards, etc. i even purchase gigabyte GA-6VLE thin client with C3-800 procesor and see, what we have with that solution, and in final i come to think, a old core 2 duo solution is best for me. then i have minimize its power consumption as far, as it acceptable for me, and put it to work...
i believe, your situation is different, and for your "home server" tasks is sufficient atom 1.6, pentium 166MMX or another low power ( and also low power consumption!) solutions...

r4350 temperatures:
i remove one PCI NIC card (3com 3c95cx), because it is close to r4350 heatsink, and may cause bad cooling for r4350.
after that i turn on computer, and measure temp via sensors command.
approx after 35 minutes it looks becomes stable, without grown - stops at 71.5 - 72.5 celsium, mostrlu show 71.5 and 72.0
peocessor temp is 36.5 celsium. when computer power up and login, videocard shows 38 celsium ( and had stabile growth), and processor has 32 celsium. now computer is turned off for about a half an hour, to cool off all things, then i turn it on again, and send low to power profile, and then measure temperature.

oh yes, power consumption ( without 3com NIC) be again 0.48A at login, voltage shows 222V.

afraid, but i see another tendency - linux, even kernel, and even without X get more and more resources hungry. if you set 2.4.x ( or even 2.2.x) kernel, and run it apache, and then see, what memory it uses, uou found, it for the same task use a lot less memory, than 2.6 or even 3.2 kernels. this looks a general problem - you can have pentium 166 mhz, win 98 SE, and office 97 - and all in that works really faster with even 32 megabytes of RAM, than fresh linux with KDE and fresh openoffice on powerful hardware ( say 1 Gb!! RAM, 2 GHz processor,and so on). i also collect old hardware,and some time ago turn on 200 mhz MMX pentium qwith w98 - and be a really surprised, how fast it turn on, and shutdown! my core 2 processor with 3 Gb ram and so on on desktop, and fresh, new linux with kde really sucks...

and now, "low consume mode" results.
after logged in system,
echo low > /sys/class/drm/card0/device/power_profile
amperage immidiatly drops from 0.48A to 0.46A, as always
temperatures are 40 degree celsius on radeon card, based on "sensors" command
after a 15 minutes we have 57 celsius on radeon card.
after 40 minutes we have 59-60 celsius on radeon, and 36 celsius on CPU.

heatsink is hot, but can keep hand on it. without "echo low", when card reaches 71 celsius, cannot keep hand longer than 2 - 3 seconds -very hot, burning...

A P3-866 is going to be slower than any atom, even the single core versions from release. C3-800 is slow, Slow, SLOW! They can be slower than intel celecrons with half the clockspeed. Difficult to find benchmarks comparing such ancient CPUs, but here a few rough comparisons-

1.6GHz single core atom beating a P3-1.13 Tulatin (and the old P3-866 isa fair bit slower than that)-
http://www.techpinas.com/2009/05/ben...eron-m-vs.html

VIA C3-800 compared to slower celerons-
http://www.cpu-world.com/CPUs/C3/VIA...281.6V%29.html

3GB wont be helping, you'll be running your memory in single channel mode. If you feel the need for sped, and/or have an older system, KDE is not a good choice IMO.

if i have 2x 512 Mb on channel A, and 2x1 Gb on channel B, i go in "single channel mode" ?
for P3 866 vs Atom 1.6: it not have a big difference in my opinion. C2D have a lot of difference, atom - not, imho.

FWIW, I run a home server on an Atom 330 (2 cores with Hyperthreading, 1.6 GHz, 1GB of RAM), currently with Debian without X. The server runs Apache, vsftpd, transmission-daemon, rsyncd, nfsd, Samba, a Squid caching proxy, a dnsmasq caching proxy, the Dovecot IMAP server and a few minor services like ntpd.
12 clients are connecting to that server, htop reports load averages that are rarely above 0.1, free reports 221 MB memory used.
I think that for a home-server that is not a desktop system or doing heavy tasks, like compiling software or Folding@Home or something similar, a dual-core Atom is more than you will need ever and light on the electricity bill (this CPU has a maximum power consumption of 8W).
From my point of view, if those few Watts are really important for you you have begun building the whole system wrong. You should have gone for a even newer system with socket LGA1155 and an power-saving Core i3 (the T versions), a slow but "green" HDD and so on. Now trying to save a few Watts with choosing different video cards is not the way I would have gone, but of course that is up to you.

what is power consumption of your whole system, not processor only?
newer system with i3 is too pricey for me.
i also plan a ST500DM005 hdd ( both - in seagate, and samsung branding -looks consume small power amounts, and stay cool, not heat up) every few watts in result make a significantly changes.
today try determine, how much eat my current hdd's, and how much "eat" dvd drive without using, but powering. in my current, old servers, i have disconnected power to dvd drive, and removed fdd.

I don't have the measurement equipment for checking power usage, but the PSU is 90W and I think it is over-dimensioned, The system is basically motherboard with CPU, not used onboard-video, RAM and a harddisk, no optical drive or floppy drive (no need for that in a server), so I doubt that total power consumption is higher than 30-35W and I didn't even look for extra power-saving devices.

Well, the information you provided is all we know about your situation. A home server for your own needs. And being overloaded by spam filtering and Joomla?

I said without X, that means no KDE. KDE is bloated.

So its consumption will be 900 kWh a year.

jlinkels

Probably not singlem channel mode then, depending on the sticks, chipset and motherboard. BTW, you are going to increase power consumption from running 4 sticks vs 2......

P3-866 will be slower than _any_ atom. The oldest, single core versions will be about 10-25% faster than a P3-866. The newer dual core atom CPUs will trash any of the old P3s.

I was in the same situation, in my case the old PCI-E graphic card stopped working and I needed to look for something else. My mainboard was a Asus P5B and I finally bought not a new graphic card but a new mainboard....

Now I have a ASRock G41C-GS which has Intel X4500 graphics onboard and the chipset is much more energy efficient than the old P965. Also I upgraded the memory from the standard 4GB DDR2 to 8 GB DDR3... currently the little server with an Intel E4300 (1.8 Ghz) and 1TB hard drive runs smooth... with a 350Watt powersupply ....

on what conditions you sort out, a "chipset is more energy efficient than old P965"?
what is your setup actual power consumption at awerage working mode /at idle ?
i think, i can run my p965 system with 150watt quality PSU, because max current from 220v for my system is 0.58A ( who do us ~128 watts).
at iddle with two sata disks it show about 0.4 - 0.41A (88 - 90.2 w), and on files copying and processor loading it gets approx 0.44 - .52A (97 - 115 w)
will be interested to get your actual stats ( measured, not "i think,it...")

Sorry I have no actual measurements, but if you dig a bit into the information provided by Intel regarding the chipsets, you will find that the P965 worked at a higher voltage than the G41 chipset.

Also because the graphic chipset is integrated into the chipset my system develops less heat, especially when the screen is powersafe mode.

With my previous setup, Asus P5B, Intel E4300, 4MB DDR2, Asus Nvidia GT9500 graphics, and 1TB HDD I was forced to use at least a 450Watt powersupply. With my new setup I have now ASRock G41C-GS, which cost about the same as a low end graphics card, 8GB DDR3 and 1TB HDD I use a slimline case which has a 350Watt powersupply....

looks like we speak completely different languages - i about a real life, you - about your fantasions based on your imaginations. i think, it makes no sense to continue...
PS Pentium 1 ( P54C and P55c) had a lot higher voltage than novadays core2duo. but it is really lower power consumption. that is one fact from real world....