sthayashi came by this weekend with his Kill-a-watt, so I thought I'd detail the power consumption results.


Main system:
- P4 2.4C, OCed to 3.0 at 1.575V
- Zalman CNPS-7000 AlCu, on Speedfan, max 1900 RPM
- Abit IC7, later-style NB HSF on Speedfan, max 3500 RPM
- Visiontek GF3, stock MHz, Enermax 80mm at lowest RPM ziptied to card
- Samsung SP1614C
- Seasonic SS-350AGX A2
- Chenbro Genie, grills removed, case damped and foamed
----Evercool 120 exhaust at <5V
----Panaflo 92 M1A exhaust at c. 5V

This system is pretty quiet minus the Seasonic A2's infamous behavior. With the case treatment, the CPU and NB fans are barely audible at max. Steve's comment was something like, "You're close enough to the noise floor that you'll probably need a fanless PSU to get much quieter." Note that he saw the machine in the middle of the day and that I find it much more audible at 3AM.

At idle, this PC pulled about 120W AC (about 90W DC). Load was tested with 2 Prime95s and 3dMark2001SE running in parallel, and used 160W AC (120W DC). The active PFC worked to spec with VA matching the power draw. Strangely, loading the GF3 did not make any significant difference in the readings. Perhaps that card is too old to include any power saving features.


Server:
- Applebred Duron 1.4 at stock.
- Barton 2500+ HSF with ghetto mod: Panaflo 80mm M1A at c. 6V
- MSI KT6V-LSR, passive NB
- S3 Savage IX PCI, passive
- Samsung SP1614C
- Antec True330
- Lian-Li PC-60USB, old version without roof fan, rear grill removed
----Panaflo 80 L1A exhaust on Zalman resistor (56ohm IIRC)

I just built this machine and have been surprised by its low noise level. While the PSU is clearly a lot louder than the entire main system, the server will not drive me crazy. I'd estimate this PC at 10db below what OCForums call "silent." This PC was tested only at idle, where it used about 70W AC (about 45W DC!!!). Power factor was roughly .65, and the VA about 105.


Monitor:
- Iiyama Vision Master 450 (model S901GT)

This is a 19" CRT. It drew about 90W AC, 130VA.


Laser Printer:
- Panasonic KX-P7105

This one was tested just for fun, since we all know lasers are power hogs. Idle: 7W. Printing: 600+W!!! I now see why the fan runs for 3-5 minutes after printing ends. We never checked the VA, but only a madman would put this on a UPS.


Power amplifier:
- Pass Labs Aleph 3

Another one for fun. The Aleph 3 is a single-ended Class-A MOSFET stereo amp, rated at 30Wx2 into 8 ohms. Its design sacrifices efficiency, and it's rated to pull 250W whenever it's on. Any power that doesn't drive speakers is dissipated as heat, which may explain why the amp is a 12"x12"x6", 35-lb aluminum heatsink. I affectionately call it "The Porcupine." Turns out that Nelson Pass was quite conservative with the specs, as my amp drew 190W and 260VA.


That's all we tested. Enough people have posted their PCs' power draw on the forum to keep me from being too surprised by those results. OTOH, the laser printer caught my attention. The KaW is definitely an interesting toy to try out. Thank you to sthayashi for bringing it by.

Hi,
Just to add to the fantastic post above, I also have a Kill-A-Watt.

My system (about as loud as they come right now):
Older Enermax 465P-VE. (2 fan model)
IC7-G with 2.4C @ 3.03 Ghz (stock cooling)
512 (2x256) of dual channel OCZ 3500 EL
ATI AIW 64MB 8500 DV
WD 120 Gb drive
Maxtor 60 GB drive
Maxtor 30 GB drive
All in a well loved but grubby Aopen HX08 (I think that is the model) giant full tower.

Kill-A-Watt reports ~124 at idle; pf keeps close to 0.65 +/- 4.

I am hard pressed to get it over 200 watts under load. (Running Prime95, Seti@home, UT2003 benchmark, defragging a drive, opening CD-ROM door).

I just received my order of quiet(er) gear - the 3700BQE and the Enermax 475 Noisetaker recently reviewed.

Yeah, overclocking has a prize....

Adrian, thanks for additional info. BTW, looks like you have a lot of room for making your PC quieter! Have you tried Speedfan for the CPU and NB?

I just installed everything in the Antec 3700BQE. It is much quieter. The stock cooling seems to bee pretty darn loud now. The IC7-G cranks down the CPU fan if it is under a preset temperature and that seems to work pretty well. I may have to give speedfan another whirl.
On the plus side the BQE has lower my temperatures by several degress - nice placement on the large fan in the back! My old case was pretty restrictive around the CPU as far as cooling other than the PSU fan directly above.
This Antec PSU is very quiet; I am putting the Enermax in later today hopefully - likely severe overkill really but I am planning on upgrading the video card soon and I have 2 more hard drives and another burner to cram in there.

Just for some more info:
Antec 3700BQE with stock Antec PSU
Antec 12cm fan
2.4C at 3.03 Ghz stock cooling
120 GB WD drive
NEC 2500A DVD (idle)
ATI AIW 8500DV (with Iceberq)

all idles at ~104 Watts with a PF of .62.

I can top it out at about 170 watts if I beat at the system pretty hard but the CPU temps stays at a reasonable ~60. It used to hit 70 without really trying in my old case.
Idle temp sticks to around 43 CPU and 21 sys. The room I am in is a basementt and fairly cool at 18 C riight now.

edit=typos. Double characters appearing when I type? wth?

Just for kicks.

Shuttle Zen
P4 3.0C underclocked to 1.5ghz, undervolted to 0.8375v
512MB 400mhz DDR
Toshiba 40GB notebook drive
Onboard ATI9100 video

Measured with a voltage tester and amp meter at the wall socket:

Idle: 28 watts
Load: 38 watts

Hm, what am I not getting here - why buy a fairly pricy 3 Ghz cpu just to clock it at 1.5? Or was that the 'just for kicks' part?
Very nice wattage reading though!

Nope...you heard him right! They are DEAD serious! I have seen many, many posts here suggesting the same thing! I have often wondered about the 'CPU underclock/undervolt' radical underground here...but I was tooooooo scared to say anything!....then you came along and did it for me!

Why indeed? If all one wants is the heat reduction (hence cooling noise reduction) of a 1.5 or 2 GHz why not just buy one instead of taking a perfectly good P4 processor and risk freezing it's brains (or one's data) by tweaking it down??? Very confusing?

Is it some Freudian 'envy' complex (....too bad my P4 can't get it up anymore....) that aims to counteract the spacial time warpage efforts of those evil, obsessive overclockers? Or is it the old Roman adage: "I Came, I Saw, I Cut it in half! " (....Take that you brute!......)



got me??? but they are serious!

(I have a AthlonXP 1800+ I will trade for an Athlon64 to save anyone underclocking problems! )

Fair enough questions.

First of all, I didn't buy a Zen or a 3.0C with the intention of running it at 1.5C. I bought the Zen because it was a quiet system. I bought the 3.0C to run at 3.0, in other words, for the performance of a 3.0.

I didn't underclock and undervolt the 3.0 so as to arrive at low wattage numbers. The wattage numbers are secondary to the purpose, which was to run completely fanless, a goal I arrived at only after buying the components that I had. But what if my intention from the start was to run completely fanless? Would it have been wiser to buy a 1.5 or 2.0 P4 as compared to buying a 3.0 and underclocking and volting it?

I honestly don't know. But I have to wonder what the wattage figures of a 1.5 and/or 2.0 are. Are they the same 10-12 watt max of the underclocked and undervolted 3.0C? The same watts that are allowing the 3.0 to run fanless, fanless without even a case fan? If not then I inadvertantly bought just the right CPU. The only P4 CPU that would allow me to run as fast as 1.5 and still be completely fanless.

I could have bought a 2.4C for instance. It, having the same 800mhz bus, would allow the same underclock and hence the same undervolt. But it would be running at 1.2 ghz instead of 1.5. The same 25% difference when both chips are running at full speed. Additionally, look at the lousy performance of the Via chips that run at 1.0 and 1.2. They run fanless like my P4 3.0@1.5, but with a mere fraction of the underclocked P4's performance. And last I knew Via systems aren't exactly inexpensive, precisely because they are or can be fanless.


So you tell me, could I really have saved some money by buying a 1.5 or 2.0 and still run fanless and be at or close to the performance level I am?

good response... and I can't answer the questions.

but I am sure we will get some good discussion on the matter!

Since I have a Kill-a-Watt and have done some fairly extensive testing with it, I thought I'd go ahead and post results here.

The base system:

185W power supply, efficiency unknown
Celeron 566 overclocked to 850 with low-profile orb sans fan
MSI-6368 mATX motherboard with onboard LAN & audio, both disabled
384MB PC133 SDRAM
Maxtor DiamondMax 9 160GB HDD
Panasonic slim laptop-sized slot-loading DVD drive (CW-8123-B)
Creative Audigy 2 sound card
ATI All-In-Wonder Radeon
2 fairly quiet temp-sensing fans

This reads 59W idling, 65-70W playing MP3s, 85W running Prime95, and 96W max (during startup).

When I reboot without the following devices, the idle wattage goes down by the following amount:

Panasonic DVD: 4W
Audigy 2: 6W (used onboard sound)
AIW Radeon: 11W (used onboard video)
each fan: ~1W
Maxtor 160GB: 11W (difference at the BIOS screen)

I also had a Pioneer 16X slot-loading DVD drive, which, oddly enough, used 6-7W more then the Panasonic laptop drive while playing DVDs but 2W less at idle. So much for laptop components always having lower power consumption.