Re: Optimal Graphic settings for Macbook Pro 15" (Mid-2015) ?

Hey! Our Macs have similar specs! I'm also on a mid-2015 MacBook Pro and I think the only difference is that my processor is faster than yours, so you might need to adjust a little, but I play with:

Sims on Medium: Objects on Low; Lights on Medium; Reflections on Medium; Visual Effects on Low; Anti-Aliasing on High; 3D resolution on Low; Render distance on High. Finally, my resolution is 1,280x800, Retina is off, Laptop Mode is off (more on that later), and Post effects are off.

These are the settings that I found worked best for my tastes. Personally I couldn't stand laptop mode, BUT it will make your game run much more smoothly, and you should be able to handle a higher resolution if you do select it. Try around to see what works for you, maybe you can use my settings as a basis. I have next to no lag right now. For the overheating, as @Bluebellflora said, make sure your Mac can breathe, and maybe check how full your SSD is, because that can't help either.

Hope this helps!