You will want to grab the version of Macs Fan Control for the version of macOS you install. [Note: never mind here! I kept reading.]
If you haven’t done so before, set up Macs Fan control so that it’s one of your start-up items (under Users & Groups in System Preferences, under your login account).
On start-up, it will nag you to buy a full version of the utility, but for setting the two fans in your model, whether 15 or 17-inch, have a look at the iFixit guide for your model to get a sense of where the fans are in relation to where the CPU and GPU live on the logic board. For my older, pre-Unibody MBP, I set the fan nearest the GPU to come on at an earlier threshold temperature and to max the fan speed at a lower max temperature than for the CPU side (which tends to run less hot on my model… results may vary depending on the model).
BUT… here’s the part which deserves especial care:
If you have not yet done so with this particular MBP, crack it open, find a soft bristle brush (like, real talk here, the $10–15 kind one uses to apply rouge/blush to one’s cheekbones… sorry boys, but your local pharmacy/druggist is likely to have something to fit the bill, and no, no one will look at you funny… it’s just a soft brush). Use the brush to thoroughly clean out both sides of the logic board, the fans (namely, the blades, after you’ve taken them out), the exhaust grilles, you name it. I have worked on mid-2010 unibody MBPs (the 13-inch, 2.4GHz variant), whose fan and exhaust was completely clogged, and the CPU, alas, was very much dead forever.
Doing a full clean-out on a 10-to-15-year-old laptop, especially if you intend to use it with any regularity, is an absolute must. This includes cleaning away the now-dried OEM thermal paste and applying new thermal paste to the CPU, PCH, and GPU. (Good, affordable thermal paste brands include Noctua and Arctic Silver; I tend to use the Noctua NT-H2, which comes with wet cleaning cloths for removing the old paste and prepping those surfaces for the new). Doing this is just like doing a full inspection, change of fluids, and tune-up on a car: preventive maintenance now can save on so many headaches down the way.
Real talk: very few Mac laptops have
zero heating issues. It’s been a long established thing over the years that thermal dissipation might get lower priority than other features.
Every series, and even specific models within a series, going back to the iBook/PowerBook days, may have certain situations where pushing the system causes the laptop to get especially hot, especially if having it on, well, your lap. Some are notably worse than others (notably, many of the the pre-unibody MBPs, especially the BTO/CTO high-end CPUs for a particular revision).
The general rule of thumb I rely on (which many models, including yours, have a sensor for, although I wouldn’t know what it’s named on your specific model) is monitoring the temperature sensor on the underside/bottom case when, at or over ~43°C for over something like 45–60 minutes, can cause second-degree burns on bare skin — especially on all models with aluminium cases. The higher that sensor goes, the less time it takes to scald your skin.
But foremost, use Macs Fan Control manual override to make sure the fans are running at maximum with the CPU and/or GPU cores are at, say, 70°C, or lower, if you prefer (and really don’t mind the sound of the fans running at their max of ~6000–6200rpm). On my pre-unibody MBP, I have mine fine-tuned to make sure the underside exceeds 43°C for no longer than a minute or two and, optimally, below 42°C at most/all times.
I’ll stress this again: give the internals a full-on clean out, and apply fresh paste after cleaning the crumbly old stuff. The iFixit guides are outstanding for the unibody MBPs. This out to help with thermal dissipation a lot better than if your MBP has never really been serviced before.
This is completely on-topic!
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