Quoth the forums:
UPDATE! Was kinda suspicious of the Indigo2 results before, so I checked... damn meter thingy was indeed showing VA instead of Watts (japes was right). Thus, I've corrected all the results with a .62 scaling, so assume these are estimates for the moment (.62 power factor should be ok for Indy, Indigo2, Octane, but not sure about Fuel and newer systems). When I can I'll retest the various configs...
Power Consumption Table for Various SGIs, in Watts (tested with a UK supply 240V AC nominal). 'Standby' usage is when the system is off, but the power cable is still live and plugged in, ie. wasted power. Use a plug with a switch on it, or switch off at the wall or extension! In the system descriptions, the number in brackets after RAM is the number of banks used. Description format is: name, CPU(s), gfx, RAM, disks, extras, note refs. The table is ordered by the unit using the least power listed first. A system described as 'Octane2' has the later Cherokee PSU, while an 'Octane' has the older Lucent PSU.
Idle/Load Power Usage
IDLE | LOAD Est? System Description Watts | Watts O2 R5K/300, 512MB (2), 36GB 10K, AV, 40X CDROM, Adaptec dual-channel UW PCI 52 | 59 Y O2 R12K/400, 1GB (4), 18GB 10K [No CDROM, no audio or AV board] 58 | 61 Y O2 R12K/400, 1GB (4), 18GB 10K, 32X CDROM [No Audio or AV board] 61 | 63 Y O2 R12K/400, 512MB (2), 36GB 10K, FC, AV, 32X CDROM 66 | 71 Y Indy R5000SC/180, 256MB (2), 4GB 50pin, XZ 74 | 82 Y Octane2 R12K/400, NONE, 1GB (2), 36GB 10K 1" (headless) 104 | 107 Y Octane2 Dual-R14K/600, NONE, 8GB (4), 36GB 10K 1" (headless) 127 | 127 Y Fuel R14K/500, V10, 1GB (1), 18GB 10K 1"  130 | 135 Y Fuel R16K/700, V12, 2GB (2), 147GB 15K, LSI U320 PCIX, Gbit, Audigy2, DVDROM  131 | 149 Y Indigo2 R10K/195, NONE, 512MB (2), 36GB 10K 1" 141 | 149 Y Octane2 R12K/400, SE, 1GB (2), 18GB+36GB 149 | 150 Y Octane2 R12K/400, V6, 1GB (2), 36GB 10K 1" 145 | 153 Y Octane2 R12K/400, MXE, 1GB (2), 36GB 10K 1" 286 | 186 Y Octane R12K/300, MXI, 384MB (3), 4GB 1" 7.2K 177 | 195 Y Octane2 Dual-R14K/600, V10, 8GB (4), 146GB+73GB, PCI cage, Gbit, QLA12160 324 | 205 Y Indigo2 R10K/195, Max/TRAM, 256MB (1), 9GB 50pin 1" 287 | 325 N Indigo2 R10K/195, Max/TRAM, 512MB (2), 36GB 10K 1", IMPACT Video 319 | 348 Y  PSU: -005  PSU: -004
Standby Power Usage (power off but live cable still connected)
Usage System Watts Est? O2 6.0 Y Indy 6.0 Y Fuel (004 PSU) 14.9 Y Fuel (005 PSU) 22.3 Y Octane2 29.8 Y Octane 32.7 Y Indigo2 (IMPACT) 32.7 Y
1. On O2, if the resolution is reduced from 1280x1024 to 640x480, the power consumption drops by 0.01A. :D
In case anyone's ever wondered, I did a quick check on the typical power consumption of a fairly ordinary Octane2 (400/V6, 4 x 256MB DIMMs, 36GB 10K disk).
When idle, the current draw is 0.97A @ 240V (UK), so the power consumption is a little under 240W, or about 1 "unit" every 4 hours (1kWh = 1kW drawn for 1 hour, about 11p in the UK just now, or 22c US).
Hammering the system with lots of apps doing things all at the same time, the current draw peaks around 1.03A, with 1.01A on average, so not much change.
Thus, assuming a typical total use of 8 hours a day (I would hope sensible people will turn off their system during lunch), the running cost is about 24p/day, or approx. 30 UKP per quarter.
Interesting though that the current draw is so low for a system like this, compared to what the PSU is rated at.
Quoth the forums:
A lot of people have recently been asking about (or at least implied a concern about) the power usage of their sgi systems.
I borrowed a friend's current clamp meter last weekend and measured the power usage for my two big SGI systems. Here are the results, in case anyone's interested. I'm also hoping to solicit other folks' experiences here -- hopefully the result may lead to a comprehensive wiki page on actual power usage by system and possibly component as well. I realize there are a lot of variables, but hopefully over time (and with a bit of crowd-sourcing) we can establish a fairly complete data set. If nothing else, it may at least be amusing for posterity.
I have the Onyx2 hooked up to my water heater circuit, which provides 244V in opposing phases, so the current was measured (and found equal) on both hot wires:
Onyx2 Deskside IR3: 2x RM10, 2x Node boards (8G ram), PCI card cage + 2x PCI cards (GbE & FC), 1x HDD, 1x CD Idle: 3.8A per phase x 2 phases x 122V AC = 927W Onyx2 Deskside IR3: same as above except only 1x Node board (4G ram) Idle: 3.2A per phase x 2 phases x 122V AC = 780W gfx fully utilized: 3.6A per phase x 122V AC = 878W So it looks like: -during gfx-intensive tasks, a 2rm IR3 uses an additional 0.8A or ~100W -a node board (IP31) full of ram uses 1.2A or about 150W.
The 4D/240 runs on standard 120V mains:
4D/240VGX twin tower: IO2, 2x IP7, 1x MC2 + 12x2MB=24MB, std 4-board vgx, 1x VP1, IO2, 2x stackable drive modules, 3x 1/2-height HDDs, 1x tape drive: Idle: 9.7A x 122V = 1183W
This is interesting because the power supply is only rated at 1050W. Perhaps the VGX transplant is too much for this little guy? It certainly makes a 16-gauge cable warm (so I've switched to 12).
Using Ian's chart convention from above, the following were taken with a Kill-O-Watt meter (110V, 15A outlets):
IDLE | LOAD System Description Watts | Watts Indigo2 R4400/200, Extreme, 128MB, 9.1GB 145 | 153 Octane2 2xR12K/400, Headless, 1.25GB, 73GB 171 | 171 Indigo2 R8000/75, Extreme, 256MB, 4.0GB 199 | 208 Origin300 4xR14K/600, None, 2GB, 18GB 219 | 219 Octane2 2xR12K/400, V12, 1.25GB, 73GB 243 | 260 Onyx2 DS 4xR12/400, IR3, 4.5GB, 73GB 945 | 1025
I loaded the systems using the Lattice screensaver for the Octane2 and Onyx2, and the solidview demo for the Indigo2. Placing any of the systems under only a processing load (such as a long c-ray benchmark) didn't seem to make any change in power usage.
The sections of the topics that dicuss power requirements...