See this Thread for the full discussion http://www.worldcommunitygrid.org/forums/wcg/...599_lastpage,yes#lastpost The discussion went a little off-topic there and so I'm creating this new thread.

About two weeks ago or so, I bought one of those kill-a-watt meters. Nearly all of my machines are on a single power strip, I put the meter in-between the strip and the wall to see what the power consumption was for the machines calculating WCG.

On the meter, there is a setting for VA (volt-amps) that is instantaneous, the other settings only accumulated over time. Other meters might have different types of readings but I wanted something simple that calculated power (VA and Watts are similar and related) and it had to be instantaneous. Note the WCG average-points are also "instantaneous" too -- if you wait long enough.

With all 11 of my machines on it, the meter read a peak of 1080 VA. The WCG average points value at that time was 69,190. So from those two numbers I calculated 64.0 points per VA.

This is the baseline. It gives me the amount of electric power I'm using to get my machines to calculate a certain number of points.

I built a new hex-core machine. I then permanently shut down 7 of the current machines (criteria was any one generating less than 5,000 average-points). And then I started up the new hex-core.

It took the last two weeks for the average-points to creep up on the new machine, and it's still rising although very slowly. Now, I have only 5 machines in all that use up 830 VA and generate 79,513 average-points. This is 95.8 points per VA.

The conclusion is clear: use more CPUs and fewer boxes. This spreads the power consumption overhead of the fan, power supply itself, memory, hard drive (I used SSD), etc to as many CPU cores as possible. The result is lower power consumption and higher average-points over all.

Hope that helps,
John

PS Here's the output of my Ruby script:

arrizza@john8:~/projects/boinc$ ruby getall.rb 
   Host   As Of      Points     Avg Pts     Credits      Type
-------- ------     -------  ----------  ----------  --------
john6     00/00    10120803      9191.0     1445829   WinHost
john10    00/00     5729640     11872.0      818520   UbuHost
john8     00/00      947933     17906.0      135419  UbuLocal
john4     00/00      420147     19299.0       60021   UbuHost
john3     00/00     3259186     21245.0      465598   UbuHost
-------- ------     -------  ----------  ----------  --------
Total     10/01    20477709     79513.0     2925387     total
per watt    830           0        95.8           0     total