|Your run-on sentence is confusing. Do you mean it only works OK when typing an email or only works OK with everything except emails?|
Sometimes, especially on this site with my old 98 machine, typing will be slow or even halt for a few seconds. It seems to be associated with the page being slow in completely loading.
If it is your email that's slow then my guess is it's doing some online activity in the background that's slowing it down.
You're not really green until you're soylent green.