Thanks - this strangely makes using the computer a more soothing experience. Tried it for a few minutes, when I turned the color back on, it seemed suddenly very loud.

I don't know. I have trouble reading text on these white backgrounds. More now than ever before.

This might be the dumbest question but is there a system performance benefit in using grayscale?

It is not a dumb question, but the answer is almost certainly not.

It wouldn't be that difficult to design a computer to process graphics a lot faster in greyscale (you need to use one byte for the color and one for the alpha) since each pixel requires less computation.

In practice if your graphic card only worked in greyscale, it wouldn't be worth the cost of development and so nobody would do it.

Who needs a computer?

Cheapo Samsung TFT > Menu > Color > Color Effect > Grayscale

Thanks, that's an interesting incentive to return to the real world for colours more often ;)

It's even better with "white on black" option.

What he said. Been doing this for a while.