Is there a difference in the speed a browser can parse a colour?

for example, the colour red, i could use the following css:

.red { color:red; color:#ff0000; color:rgb(255,0,0); }

these all produce the same result, text colour red, but in the sense of efficiency, what is the best to go with?

I realize that using the text 'red', is the lowest character count, and for minimalizing the document size that would be the best to choose, is that what should determine the choice?

The only reason im asking this is literally everything on a website has varying colours, so if there is a small change that could add to a few miliseconds, it could possibly be worth using the best method.