Setting that makes the screen dim when it's not white

Is there some setting which makes the screen dim when it's not nearly all white?

I'm working in one maximized window, which has an all white background and some text. If I switch to another window which has a light background, even near white, then switch back to the "white" window, there is a very brief pause before the screen gets brighter again. I never notice the brightness dimming when I switch to the off-white window, but when I switch back to the white window, the screen suddenly brightens.

TIA.

I opened Power Options from the start menu and got a very different window. I had a choice between "Energy Saver" and "Power Saver" because, apparently, in Redmond there is a different "energy" and "power" (I will have to discuss this with my Physics Ph.D. friend). What a pair of choices, huh?

After searching, I found a "High Performance" setting.

Edit: It had no effect.

UsernameIssues said:

If it is really annoying, then change the NVIDIA drivers. Even if it means using an older version.

Are there some driver settings I can change?
How do you know I have NVIDIA (that might be information on old system you're looking at). How can I find what I have?

It says AMD Radeon HD 8450G.

I notice a Roll Back Driver button. Maybe that will help?

UsernameIssues said:

You could try a roll back. It might help. It should not hurt anything.

It could hurt something after all. First, it set my resolution to the lowest possible level -- something like 10x20. I fixed that up, but now it won't recognize two monitors? The monitor is plugged in.

How can I get multiple monitors back? (And how does one work without them?)