Need Help Understanding DEV FPS Screen Cyptic Color Codes

Hi in fine tuning my 3070ti performance like to better understand what is going on here (3 questions):

  1. At the bottom the GPU Memory changes color… lowest use is white, then yellow and then orange like this and maybe red I forget.

In Performance on Task Manager I will get readings like:

Dedicated GPU Memory 7.3/8.0
Shared GPU Memory 2.6/31.6
GPU Memory 9.9/39.6

I get that the Shared memory is the computer RAM

Is there some rhyme or reason here as I seem to get stutters when I go over 6.5 on GPU Mem…???

  1. The limited by main thread I belie means limited by the CPU, weird as I have a Ryzen 7950?

  2. Finally, at one point I was able to change the top RED color to GREEN by a certain criteria… like to have it green if I run better than 60 FPS.

Thanks for help… I searched and could not find explanations of this.