I apologize for not being able to recall who made the following suggestion, I believe on Twitter (I tried but could not find the tweet), but I found this tip to be a good one.
The first time that I select a ribbon tab other than the "Home" tab, I take a moment and select all of the tabs one by one. The reason for this is that Civil 3D puts the tabs in cached memory the first time that it is used, and it takes a second or three to do that. Once cached the ribbons change very quickly.
This has helped me by preventing any ribbon switching lag at unexpected moments. I control when that happens, and it is usually right at the beginning of a drawing session before I get engrossed with the design.
I hope that some of you find this helpful.
Be Better! ...Plan ahead in order to work faster.