Right guys. I'm here to possibly make your day!!
This may sound like an advert for the developer (well it sort of is) but if my initial testing works out which it looks like it will, this has saved me from upgrading from a perfectly great laptop albeit the usual fan issue we all know and love.
Mine is an i7 2015 Macbook Pro 15 inch, 16gb, 1TB, bought new by myself. However after many years, I was just about to sell on eBay cheap and buy a Macbook Air M1 because guess what it doesn't have to spoil your productive work day???
I've searched and tried all the usual !@££$%$%^ that Apple tells us with SMC, clean fans etc etc. Get this, Apple even replaced the motherboard near the end of its 3yr care support a few years back when they reckoned one of the temp sensors was playing up. Can't prove that but it didn't fix the fan issue anyway.
No idea how but I literally stumbled on this 30 minutes ago - https://www.reddit.com/r/macbookpro/comments/jiy3n8/macbook_pro_mid_2015_fan_noise/
Has anyway plugged in an external monitor for the fans to scream like a banshee until removed? 8 hour productive day ruined by T.C. refusing to give a $$$$$$ to his users? Well no more for me, thank you sir.
The app disables Intel Turbo Boost in short. You may lose some performance, haven't tested long enough to be 100% but I'm a heavy Chrome user for work. 3-4 profiles usually loaded with a bunch of tabs, but plugging my monitor in, running those and then loading Gimp to stress it, silence was golden. It has the usual app functionality so can turn off and make the babies burn up again. From what I can tell from my (as you can probably tell giddy testing) the fans will come on if needed, but as the Intel part is not boosting, the fans aren't being required as much.
Anyway if you try and it works, consider purchasing the pro version for the developer. I will once I have.
Please can I really stress to the moderators of the forums, this is a real post and not an advert to purchase a 3rd party tool. I just hope this does fix the issue and helps others.
If it does guys, tell the world that these old Macbooks are still worth using. No need to give back to Apple just yet to recycle them.