Hi all,
Speaking anecdotally, do people find a lot of switching costs when running multiple projects at once? I'm finding my PC can be fully occupied when running just Einstein and Denis, but I want to do more because (a) I care about other projects, and (b) as evidenced by these forums, projects sometimes have downtime/stop sending tasks. If I sign up for ~8 projects on a machine that can run ~2 at a time, does it meaningfully reduce the machine's efficiency? Or do you normally find switching costs to be minimal?

It will help keep your host fully occupied all the time, even when a project is down or out of work. The efficiency won't change. The Boinc client will balance out the work credits among all your projects based on your resource share allotment between all projects.

Just a warning, when you add new projects, they will run exclusively for a while and prevent your Einstein and Denis tasks from running. The reason is because of "credit debt" that the client will try to balance out. Eventually when the debt for the newer projects is paid against your average credits for Einstein and Denis, the host will start to run all projects equally based on the resource share allotments.

The balancing can take a short time or a long time and is caused by the different credit systems and awards the different projects use. Some projects award high credit for tasks and some low credit. This imbalance needs to be taken out by the client using the REC algorithm in the client. REC or Recent Estimate Credit has a xml tag in the cc_config.xml file in the client directory.

You can speed up the balancing process by changing the default value in the file from ten days to 1 day. This is done by changing the parameter value. Change this in the <Options> section

<rec_half_life_days>10.000000</rec_half_life_days> to this

<rec_half_life_days>1.000000</rec_half_life_days>

and save the file. Then re-read config files in the Manager menu to apply the new value.