Power saving steps?

[enmaku]

So I've got a couple of dual 5830 rigs built and parts are on the way for a couple more. I've got them plugged into a kill-a-watt and the two of them combined plus a small fan are eating about 800W. I'm worried that a third box on the same circuit might pop a breaker. I can always move the new boxes to a different circuit but for cooling purposes I'd like to squeeze at least one more onto this circuit. Does anyone have any tips/tricks for reducing the power consumption of the rigs? They contain only the basics (cpu/ram/mobo/hd). I'm assuming the cards need all their supplemental power connectors and such and I've got the drive set to spin down.

Any magic tricks I'm missing?

[Fuzzy]

the power your GPUs are eating is pretty much fixed, unless you underclock the GPU, but your hash rate will drop, and you don't want to save power that way. Here's what I did:

-UNDER clock and UNDER volt your CPU, there is a lot of idle power wasted on older, pre-CORE CPUs

-Boot off of a usb drive, so no spinning HDD is required.

-disable onboard devices (raid controllers, audio chipsets etc) in the bios

-Down clock the video memory, this hasn't show much power savings, but may reduce heat.

-Use only 1 stick if ram

-Remove all non essential peripherals, floppys, dvd-rom drives, soundcards

-Remember to physically power off your monitors, as they still consume power in standby

Even after all this, I saved maybe 30w out of 1000 

[hermolegy]

if the color of websites pages  is black then a lot of energy is save , as a large no of pc's are use world wide.

[mapwow]

if the color of websites pages  is black then a lot of energy is save , as a large no of pc's are use world wide.

Displaying black on CRT monitors saves energy. However it actually uses more energy to display black than white on LCDs. CRTs are old-style monitors that are thick and look like old TVs. LCDs are currently much more popular and are thin.

Reference: http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-black-is

[enmaku]

the power your GPUs are eating is pretty much fixed, unless you underclock the GPU, but your hash rate will drop, and you don't want to save power that way. Here's what I did:

-UNDER clock and UNDER volt your CPU, there is a lot of idle power wasted on older, pre-CORE CPUs

-Boot off of a usb drive, so no spinning HDD is required.

-disable onboard devices (raid controllers, audio chipsets etc) in the bios

-Down clock the video memory, this hasn't show much power savings, but may reduce heat.

-Use only 1 stick if ram

-Remove all non essential peripherals, floppys, dvd-rom drives, soundcards

-Remember to physically power off your monitors, as they still consume power in standby

Even after all this, I saved maybe 30w out of 1000 

Aside from the USB stick idea, which I might just do this weekend, I've already done all of the above. I guess I'm just going to have to spread the rest of my (unbuilt) rigs around the house to avoid popping breakers. I didn't want to do this because I've got a portable AC unit already that will keep that one room cool, even with five or six rigs dumping 1300 BTU/H each into the air, now I'm going to have to spend more money and power cooling them all, or just have one very uncomfortably hot room.

[enmaku]

It also occurs to me that my math might be off or my understanding of standard house wiring could be off. Does anyone with a mid-to-large scale mining operation have any comments about how you addressed this particular "problem of scale"? How many rigs can I actually run on a single circuit at 400W each? Is it at all possible (likely) that two outlets in one room could actually be on different circuits?

[enmaku]

Nope, my math was right. I predicted rig #4 would be OK when idle and pop the breaker under load and sure enough

Guess I'll be going to Home Depot to pick up another portable AC unit this weekend. If my apartment management wasn't willing to believe my AC was inadequate before they'll certainly cry foul with 5200 BTUs worth of computer heat being pumped into the air