Your system has two graphics engines! The intergraded within the CPU (Intel HD Graphics 530) and the dedicated GPU (AMD Radeon Pro 450, 455, or 460). When you are using Photoshop or other heavy graphics app your system runs the dedicated GPU (unless you tell it within the energy setting). When you just start up your system it will use the intergraded graphics until the better graphics is needed.

So why is this important? Basically, its a matter of heat! While the performance of the intergraded graphics is not as good as the dedicated GPU which runs hotter, the amount of heat that can buildup within your system can cook things! All of Apples newer system have a an issue with the T-CON board which instead of being placed in a location which tends to be cooler they placed it very close to the CPU/GPU’s heat sink system so if the fans fail to cool the system the T-Con can be damaged by excessive heat!

So what to do? First is make sure the system is clean internally of dust (case, fans and logic board). The next is to install a good thermal management program like TG Pro which I strongly recommend! With it you can see what the sensors are sensing as well as push the fans harder when you have set a set point or when you need to make sure your system is at its best cooling (turbo). You also need to make sure the vents are not blocked. Don’t use your system on a bed or other cloth surface.

I would also make sure the drive has enough free space. SSD’s while fast also have housecleaning tasks which can cause the CPU and drive heat up when there is not enough free space. Ideally, You want to have as a minim 1/4 of the drive empty (more if 512 or smaller - 1/3) and you’ll want to reduce the amount of apps open at the same time. As an example Chrome is a memory hog! And when memory is lean will leverage Virtual RAM which is space on the drive to emulate RAM. Photoshop and other graphics apps also leverage scratch space which again uses the drive. The more free space you have the better! As an example I have a 2 TB SSD in my 2013 Mac Pro which I use photoshop and the images I work on are quite large, I need about half of the drive free fo me to render and I’m not running anything else on the system (dedicated to image work)