Thanks for the reply. I've made a few small changes, but the fact is that the laptop is not heavily used and was given very nearly free reign for BOINC when not in use, and did not run until the laptop had been unused for 5 minutes.

At my last job, I had access to multiple systems running lab machines, and let's face it, most of the time they were entirely idle. I had BOINC on all of them, running when the lab system was idle, with no impact on lab work. I did have another laptop here running BOINC, but when it started making noises like the fan was going to fail, it's shut down for now.

PrimeGrid sends a lot of relatively small jobs, always complete early. I observe there that the estimated time to completion drops as soon as the task is begun.
Einstein sends a number of jobs, fewer and larger than PrimeGrid and always complete early.

Right now I've put both those projects on 'no new tasks' and I'll see what happens after that, and update later.

I endorse Grant's suggestions, but I'll just mention some slight differences I use on my relatively new laptop.
I worry about temperatures/cooling too, but I'm getting away with 50% of the CPUs without fan problems or throttling.
By all means start with 25% (2 of 8) cores and if it works much better, try 37.5% (3 of 8) before stretching to 50%.

In terms of time unused before Boinc starts, clear the fields and unselect them. I believe this defaults to 1 minute, which I think is plenty.
Lots can happen in 5 minutes - even just touching the mouse or keyboard. I always suspect this makes a huge difference with no benefit to you or Boinc.

In fact, I have everything unselected on the computing tab, except "Leave non-GPU tasks in memory while suspended"

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