How to reduce power consumption?

[SmallWalrus]

I've recently turned an old X61s into a pfSense router, and it works *great* except one thing that bothers me is that it pulls around 20W through the wattmeter even though it's only running at 400mhz (according to the FreeBSD console).

I've actually tried connecting a headless X61s to the same AC adapter and I got the same readout, so I am starting to suspect that...
1) the monitor uses that little power
2) the AC adapter is not that efficient and uses that much power no matter what

Has anyone else had a similar experience in using old Thinkpads as routers? What do you do to keep the cents down on your power bill?

[Colonel O'Neill]

Does it draw the same amount in a fully drivered Windows install?

[SmallWalrus]

Does it draw the same amount in a fully drivered Windows install?

I have no idea, will have to test that out

[ozzymud]

With my 760's, I removed the spinning IDE(PATA) drives and use a CF2IDE adapter with a 4GB CF flash card... this greatly improved battery life (and for a router would be plenty fast enough).

Let my break out my kill-a-watt and test various AC adapters for draw in various situations... will report back

EDIT:

here is what i found:

1-6 powered off - chardged battery
*26-31 bios post
*23 idle - dos
*28-29 idle - login win95
*29-30 login - login sound
*24-25 disk access windows 95
*20 idle desktop
16 idle desktop (screen went off)
1 when not plugged into laptop
*22-24 during shutdown
*31 charging idle DOS
14-16 charging power on lid closed dos
13 charging (from 96%) power off
(this gradually dropped to 10 as it reached full charge, at which point the reading would occasionally change from 1 to 6ish and back)


then i switched to the Linux CF card...

*28-29 grub menu
*32-34 boot sequence
*24-25 login prompt
*32-34 during login
*24 idle at prompt
*30-35 during startx
*24 idle IceWM desktop
*17 idle desktop (screen went off)
*29 during shutdown X
*24 idle at prompt
*27-33 during shutdown -h now
*24 sitting at "System Halted"

* 4 watts lower in all modes when sliding brightness down to lowest, the monitor accounts for 4 watts when on at lowest brightness or 8 at highest)

At no time when the battery was 100% did the AC adapter draw 1 when the machine was powered on, so I assume when powered by AC the laptop only runs from AC and does not utilize the battery at all

Somewhere i got a spinning disk around, I'll check how much it draws over my poor man's SSD

EDIT 2:

plugged in a 2.1GB 17mm drive, all results were roughly 4 watts lower, except for drive accessing... like in dos, at c:\ doing dir /s both drives caused wattage to goto about 29 watts...
assuming this is the IDE chipset using more power along with the cpu.

both idle the CF drew like 4 watts less.

[SmallWalrus]

Wow, thanks for this very comprehensive test. It is strange, your figures seem quite similar to mine. I am really wondering how other forumers get wonderful figures like 8W after removing their wireless cards and finger print readers.

[ozzymud]

as an addendum, I also had a wired pcmcia ethernet card installed... this also accounted for another 1 watt... for a router there would be 2 for 2 watts more for a grand total of 20(idle Linux)+2(nics)-4(screen off)=18W

There is also no drive in the UltraBay atm... normally I have a CD installed there, but a router probably wouldn't have one either(just install as needed).

With the CPU itself being 5W of the above total... and it being a P166... it would be hard to see how a modern processor (excluding the Atom type machines) would be able to get so far down there.

I'm now curious about my newer HP/Compaq M2005US (1.6GHz AMD single core iirc)... I also used the same type CF2IDE adapter in it with a 233x 8GB card... wonder what it draws... will have to look

EDIT: Screen is still 4 watts from bright to dim on the Compaq

CPU is Sempron 2800+ (1.6GHz)
35-36 power off - charging (unknown charge level)
64-72 post thru login
62-63 during xp scan disk (didn't shut down last time properly )
67-73 continuing to boot
63 at idle desktop (battery at 10% by this point)
long wait for battery to charge

Finally charged... 28 watts idle at desktop with wired network(internal) on, wireless off, CD installed, hard disk is Compact Flash SSD, battery at 100%. Drops to 24W when monitor is turned off.

So, newer monitor = same wattage
newer back-light = same wattage
newer system = as expected, more wattage overall

And again, when the laptop is plugged in, it's only interaction with the battery is for charging, seems to run fully from the AC adapter otherwise

[mazzinia]

Sorry to intrude, but isn't an X61 a bit overkill (and a bit new still, it's perfectly usable in daily life still) to use as a router ?
An x30 or older would more than suffice, imho

[ozzymud]

My thinking as well.. what a waste of an Intel Core 2 Duo... but maybe the OP has better machines and this one is sitting wasted.

My Asus RT-N16 router is:
Unit CPU = Broadcom4718A, 533 MHz (Factory clocked to 480MHz)
Unit RAM = 128 MB (2x 64MB)


So yea... something like a ThinkPad 600X would be more suitable... but even machines like the 760 series (P150/P166) will work although I could see them getting into trouble if you do torrents and such.

[SmallWalrus]

I actually isolated the fault down to the power adapter, when I unplugged the laptop from the adapter, it still drew 24W!

Replacing it with another adapter brought things down to 15W, now I am happy

[SmallWalrus]

Sorry to intrude, but isn't an X61 a bit overkill (and a bit new still, it's perfectly usable in daily life still) to use as a router ?
An x30 or older would more than suffice, imho

Yeah, but I don't have any extra X30s sitting around, and to buy one off fleabay will cost quite a bit. Since a X61s don't sell for much these days as well, and it will cost me quite a lot to fix it up with a new monitor (this one's broken), it actually isn't too bad.

A headless X61 (non-S) can be gotten on fleabay for about US$40 or US$50 if you look hard

[ozzymud]

All of mine i checked while unplugged from the laptop drew 1 watt... so yea, definitely a faulty brick.

Think I'll check all the other 30 or so in the house now... cell phones, monitors, game consoles, routers, etc etc