Date: 08 Jun 2004 20:18:28 -0400 From: Mike Jeays <Mike.Jeays@rogers.com> To: Bill Moran <wmoran@potentialtech.com> Cc: freebsd-questions@freebsd.org Subject: Re: Leaving a server on all day Message-ID: <1086740308.89356.6.camel@chaucer> In-Reply-To: <20040608160605.429485d5.wmoran@potentialtech.com> References: <20040608122101.GA68204@dogma.freebsd-uk.eu.org> <87zn7ednwg.fsf@pele.r.caley.org.uk> <20040608172756.GA70798@dogma.freebsd-uk.eu.org> <20040608135903.024729b8.wmoran@potentialtech.com> <6CCB3AEC-B97C-11D8-8148-003065ABFD92@mac.com> <20040608160605.429485d5.wmoran@potentialtech.com>
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On Tue, 2004-06-08 at 16:06, Bill Moran wrote: > Charles Swiger <cswiger@mac.com> wrote: > > > On Jun 8, 2004, at 1:59 PM, Bill Moran wrote: > > >> Hopefully I'll get my flat screen back soon from repair. I guess > > >> those use > > >> less power, right? > > > > > > I remember having this conversation with someone not too long ago, and > > > our > > > consensus was that flat screens used just as much power as tube > > > monitors. Don't > > > hold me to that, though, I don't seem to remember our testing > > > technique as being > > > very ... uhm ... "scientific". > > > > No need to guess, use an amp-meter. :-) > > What a crazy idea. > > I seem to remember plugging monitors into a UPS in an attempt to use the cheesy > "load meter" lights to tell which was drawing more juice, when that didn't > show us any difference, we tried watching the power meter outside ... trying to > guess which monitor made it spin faster ... > > > >> Also, a 1.8GHz Athlon won't use any more power than > > >> necessary during idle time, right? > > > > > > Different processors are different. Many newer CPUs will throttle > > > their power > > > consumption while the machine is idle, but most older ones can't do > > > this. > > > You'll need to research the specific CPU + motherboard to see if this > > > is > > > available or not, but (as far as my lousy memory serves) Athlons in > > > the 1.8G > > > range don't support reduced power during non-usage, and will consume > > > just as > > > many watts while the system is idle as while it's doing a buildworld. > > > > A 1.8GHz AMD is likely to be a Barton, or possibly a later-model > > Thoroughbred. The CPU should have AMD's PowerNow! capabilities if APCI > > is enabled, and they should also significantly reduce power consumption > > if the OS runs the HLT instruction in the idle loop. > > Ahh ... didn't know the 1.8s had that in them. > > > I have one machine with an AMD 1800+ (1.54 MHz T'bred-B), which runs at > > perhaps 48 or 50 C if the system is idle. If I run something like > > SETI@Home for a day or so, the CPU will go up to around 56 or even 57 C > > as a result of the load. The difference in thermal output due to load > > is very obvious. > > But is thermal output a reliable indicator of power usage? Logically, it seems > like it would be, but I'd hate to assume. Virtually all the power used gets converted into heat that will heat up your room. A typical workstation might use 50 watts when idle. If power is 5 cents per KW=hour, it will cost you about $2 a month. 50 watts used to heat your room won't make a lot of difference - just a bit less than a 60 watt light bulb...
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