Unable to pinpoint reason. Used the same blend file in both 2.83.5 and 2.90. Within a few minutes of moving 1172 vert. subject (not huge) the fan and my SSD iMac starts getting louder and the heat starts pumping out of the back unlike anything I have experienced before. I tried to see what Activity Monitor could show as the cause, but it looks about the same in 2.83.5.
I just wanted to call it to someone's attention, Just loading this file into 2.90 and moving it around and editing doesn't seem to consistently make the heating happen. This is the first day using this version and will continue to watch for what triggers the high GPU usage. I am not using the EEVEE render mode or any image render to make this happen. VERY STRANGE-- it won't come back and be reproducible during each session. Hopefully I am the only one who notices this "ghost". Write if you want specific other info.

Two problems, one critical:

1. When Blender 2.90 is minimized to the dock, it suddenly accelerates the Idle Wake Ups and will suddenly go to over 200.and the system starting immediately with the fan on the SSD HD computer (normally silent) suddenly getting louder and faster with generated. heat !! IF left in this state, it seems like the computer could be burned out. I had to shut off Blender to stop the process. Picture of Activity Monitor when Blender minimized and suddenly overheating system.

2. Showing the Activity state when using Wireframe Viewport Shading Solid. When using this mode, zooming the subject in Edit mode in and out causes GPU % to jump up -- had it a 86% briefly (shown at 80%). I didn't test Object mode zooming. The mode immediately locks in at about 56% and stays there even when nothing is selected or movement happening. It doesn't release quickly with another mode selected either. This seems another more minor source of overheating. I was surprised that most other Viewport modes including EEVEE were less demanding on the system.

See the above comments on Minimizing Blender 2.90! Very surprising. I had to add this comment because I didn't see how to change Status when I added the above.

Yes, I am currently using 2.83.5 with no difficulties. My problem is that I don't have adequate tools to see what is happening with the overheating with the meager Apple tools given. All I can say is that I was shocked when Minimizing to the Dock caused the system to heat and loud fan noise to increase. IF I had just left the room as normal the system could have shut down from thermal overload (I HOPE). I acted just like a render on my 2009 iMac with massive overheating except this was more immediate so I noticed it. I checked to make sure it wasn't rendering. I also checked to see if somehow I had signed up to be part of a server rendering farm (done that). I won't be using 2.90 until this "bomb" is defused. I am surprised it hasn't happened to any others yet. Almost seems like a malware, it is so unexpected.
I am also surprised that high GPU happens primarily with the Solid mode and that it requires so much more than the more refined modes or EEVEE.

OK, caught it in the act this morning (see screenshot). I was using Solid with X-ray view and holding down "." to orbit around to check edit when the fan started getting louder. etc. I think it may be something to do with having both views selected at the same time. Changing from Solid to wire-frame drops the GPU usage immediately, other wise it just hangs at 86% - 92% usage until switched or computer melts..... I assume there is someone else there who is using a Mac to check this out.

@Ankit Meel (ankitm), @Sebastián Barschkis (sebbas) If I remember correctly you have mac machine. Can you check this out?

I'll check it soon but noting another report here: T80541: Solid View -->>Thermal Overload
I don't have Radeon Pro Vega 48, just an Intel HD 6000.

@Ankit Meel (ankitm) The author is also @Paul Muns (dznwks) on T80541: Solid View -->>Thermal Overload

A clue is that there is no problem with version 2.83.5 (using same blend file too) with this combination of views and I was only able to get the GPU up to 50% with a lot of moving around but then it dropped back immediately when I stopped to zero. Some code difference in 2.90 is causing the GPU to jump to 80%+ and hang there regardless of movement.
I have notified Apple about the problem as well -- whatever the code is, it could be "dangerous" for the way OSX is dealing with it.....

What is Invalid is that the issue is resolved--not so fast! Invalid means the same as Resolved? And Normal means all is fine? The labels need a little more clarification.....

Thank you Robert for reopening. I dearly need that view option to do effective Modeling and every time I click onto it I can hear the fan starting to work faster and heat starting to accumulate. I can't believe no one else has had this problem or perhaps doesn't recognize the cause. I am adding this message because I am using 2.91alpha and it has the same problem. I will continue to download and use the latest experimental version to see if anything has changed.

I just got the latest build: Blender-2.91.0-099ce95ef36d-macOS. I discovered that in LAYOUT mode this doesn't happen. It only happens in MODELING mode and it happens every time. Modeling mode hates my GPU and will overheat it into a molten mass if left un-aware, No overheating while Editing in Layout mode. Hint Hint.