I think you are referring to GB as in gigabytes. There aren’t any differences between the sizes or revisions. But some people say it’s harder to read the screen on the silver model because of the slight tint.
@miikerman wrote:
The screen on the silver version definitely is more difficult to read than on the other colors (IMHO, they’re all a bit difficult outside in the sun).
My red and black ones are…I have to go from all the way low brightness to over half, and that’s with cupping my hands over the screen.