If what you describe is a 4 core, hyperthreaded to 8, then setting the processor use to 50 percent and the cputime to 50 percent actually yields near 50 percent usage of maximum, yet gives least heat alert on laptops. The trick is, that at 50 percent of processors, you are really using the 4 physical cores -without- hyperthreading. Then throttling this down to the suggested level gives a 1 second pause, 1 second run cputime use for least firing of the ventilator, which is the annoying bit.

First, thank you for spending the time to answer my post.

@lavaflow
Yes, the core i7 is 4 cores hyperthreaded to 8. I find the The 50%/50% suggestion great, but unfortunately my father is still not happy with it.

@Crystal Pellet
We have an external base with fan under the laptop in use. I think my father is more worried with the heat that is fealt when we put a hand near the side of the laptop, the graph of CPU usage in the system monitor and the effect of the usage of Boinc on the lifespan of the laptop than with the noise, although this could also be a reason for his concern. But I'll try suggesting him TThrottle in the next opportunity to see if he'll find it useful, thanks for the tip!

Heat from a laptop is only a problem if it's on your lap! I have mine on a hard surface so that there is good airflow and it runs 24/7 at 100% CPU (apart from when I take it somewhere with me, of course). As I write this the temperature is 81/83 for cores 0/1 running MCM1. The current beta made it run hotter, and the temperature goes up if I watch videos 'cos it's using the GPU too. I have temperature warnings set for 90/95 -- not because I'm afraid that anything will happen to destroy the machine, but because when it gets that hot the CPU is automatically throttled down and so the output goes down. At that point I get the vacuum cleaner out and clean out the dust from the vents!

I've had this machine for over 5.5 years and it's just fine running like this. A previous laptop I had died of a fan failure when it was so old that I didn't bother to replace the fan.

Engineers have told me that machines get far more stress from being turned off and on again than they do from being run flat out 24/7. Tell your father to stop worrying -- or get him to voice his specific concerns so that we can address them.

@vlado101 and @Apis Tintinnambulator
I would probably do the same if the laptop was mine, but since it's not my hands are tied.

@Crystal Pellet
We tried TThrottle, but it seemed confusing to use. But I got him to go from 25%/60% to 50%/60%. Yay!

Must be the high fan noise that's getting to your father. Unfortunately in a laptop there's really no way to reduce this except for maybe just running one work unit at a time.

If you want a 24/7 stable power cruncher, you really need to go the desktop route with a huge fan cooler (hyper 212 or equivalent). You'll be able to run 8 work units at a time and not even know the computer is on.