This is by design.

There is a solution. In your preferences, you can set BOINC to suspend computation after a period of user inactivity. Or, just use the "Power Saving" preset.

Here's a screenshot copy from the Start Here forum topic BOINC: Website Device Profile & Local Preferences Information

You're looking for the "Stop work after computer is idle for X minutes" option.

Didactylos: Thanks for the information. I do have a follow-up question though. Why was BOINC designed to interfere with system standby, without notification to the end user? Of course it will result in additional cycles being generated, in the short term, perhaps as long as a week or two, but once the end user discovers this "feature" which caused his PC to remain powered all night long, then there is a considerable risk he may uninstall the client, without bothering to post a question in the forums. In my case, I have the luxury of spare time to work on this issue and learn more. From what I have seen, though, the BOINC client could use additional programmers/software designers, though due to the non-profit nature of the project, one might expect and tolerate a few rough edges here and there.

Sekerob: Thanks very much. Your message was the key. It looks as if the web-based "Device Manager" configuration offers a potential solution for me, not found in the PC-based preferences. I have selected custom device manager profiles, but my selections are not reflected on the web site. According to the information provided on the web site, I won't know whether my changes have "taken" until the next time my PC's communicate with the grid, in .2 of a day. When these changes are reflected on the web site, I can begin the series of experiments to determine whether or not S3 mode works.

Retsof: Magic packets aren't the problem, though they could be for another user. In my situation, the computers have been going to S3 sleep for two months without issue, despite actively downloading files from the network and the internet (yes, downloads were interrupted in order for the computer to get its sleep).

Hibernation mode writes to disk the contents of the RAM, rather than keeping applications in RAM, and therefore the computer takes longer to wake up. S3 wakes up in two seconds at most. The electricity consumed by keeping a charge in the RAM chips is probably quite minimal, though I haven't examined actual consumption. Also, I have experienced technical problems with hibernation mode before, whereas this is the first problem I've ever encountered with S3 mode. And the problem was not with S3 mode per se, but with the BOINC client, which according to Didactylos was actually designed to disrupt S3 mode. (?!) Oh, well.

Your hardware setup indeed sounds optimal if you are leaving the computers on 24/7. Even more efficient is if you're running motherboards with on-board video support instead of using a graphic card, and on-board sound. Global warming being where it is, not to mention the financial cost of electricity, I do have qualms against leaving any device on longer than absolutely necessary. Hopefully, one day, the nations of the world will focus their priorities on harnessing nuclear energy, the obvious practical solution, instead of wasting time and money on counter-productive warfare to defend existing sources of fossil fuels.

Thanks to all three of you. May our mutual efforts pay a dividend in the form of saved lives and enhanced human happiness and productivity!

I changed my profile on the online web site earlier today, but the changes did not migrate to my machines after twelve hours. Also, I did not find the web client a convenient or self-explanatory method of changing one's device profile. I would prefer options within the PC application, easily accessible and intuitive. Also, I don't know why I had to go through this procedure in the first place. Upon reflection, I am dismayed by the way BOINC behaved on my desktop (not laptop) PC's. There wasn't any notification of this secretive change to my powersaving configuration, which was carefully planned and deployed on a number of PC's. This angers me. It is rather creepy behavior, not at all what one would expect from a charity. Forthrightness and transparent behavior are the hallmarks of good and honest people. Secrets and hidden tricks are not.

I have begun to question the ultimate motives and purposes of world community grid. I once was a believer, but my initial assumption of forthrightness on the part of WCG has now been compromised. I would feel naive to assume that my computer cycles are being employed to find a cure for cancer, etc. Perhaps instead, the ultimate aim is to design biological weapons, clone human beings to make a master race, or design chemical weapons. Or perhaps merely the processing time is sold to third parties for profit. We would not, as end users, have anyway of really knowing the ultimate truth of the matter. For these reasons, I am opting to uninstall BOINC.

Hi, drakeselah.

We are aware of the problems with the preferences. At the moment, it's a mess. However, a desire to retain backwards compatibility is slowing down change. We're working on it.

Now, I feel I need to correct a misapprehension. The reason your computer doesn't sleep is purely because BOINC is computing. At no point does BOINC change your power settings. Laptops go into a different sleep mode; they ignore whether the processor is active or not. Desktops don't do that. They assume that if your computer is busy, then you want it to be busy.

All the BOINC power saving preference does is suspend computation after a period so that the normal Windows power management can see the processor isn't in use, and shut down or sleep automatically.

If you are worried about WCG's credibility, perhaps read this article in Scientific American? http://www.sciam.com/article.cfm?id=cancer-software-technology

Also, WCG is not a charity. It is run by IBM, and they fully fund it, they never get any money in return.