I just run a small test on my laptop which is the latest spec and 32 GB ram and run for one hour continuously with 100 threads and 100% CPU usage and my hash rate was around 75 H/s got around 120+ Santoshi and which I think very less for the electricity we spend for running one hour. But it may be good for people where they get cheat electricity.
I think the best idea is to run it in the background while you are using your PC for something else so it's only costing a little extra electricity in the CPU. Doing this it is running at about breakeven on my 4-year-old i5 so something more modern like you are talking about should be running in profit.
If you run it in the background then your PC will slow down and your other work also may slow down. I also don't know how it will affect my PC function in the long run for utilizing CPU power always at higher side. I don't think it is worth at least for myself and don't want to risk my PC to earn these small amounts of bitcoins.