I usually check the new threads twice a week or so, no big deal ten or so new threads isn't anything to go through. Every once and awhile though I wont be on for a week or two weeks sometimes a month, 40 or sometimes 70 threads is a big deal now, to effectively find what I'm looking for.

My Suggestion:
Add a new button and checkboxes to the forum page. Leave the button as an Check All Read but then the second button marks only the checked threads as read.

agree!