Not to flog a dead horse but I have also heard even a cluster of 40 cpus will not mine efficiently. Assuming they are mixed cpus hash rates could be all over the place. Also if you don't want people to know the computers are mining, you won't be able to mine with 100% cpu usage otherwise the computers will be very choppy and basically unusable. But like others above me have said you could run the mining software in the background and have each one as a different pool worker. Curious to hear actual results of a setup like this.
The OP mentioned that he intended specifically to run at 50% CPU, not 100% - so that point is covered. I'm curious though - through my lurkings I too have heard that each computer should be linked to its own worker - specifically for troubleshooting purposes. Is there any other reason this would be important? What would be the harm / benefit in having all the computers mine through one worker Vs. an individual one for each?
Thanks!