Directly, not much; but indirectly, a lot. Seems a bit paradoxical, but it’s true.
To understand this, you have to understand the idea of conducting pre-boards. Pre boards are conducted by schools to prepare students for their final exams. Teachers like to ensure the completion of course and the revision a month before boards, and it is really helpful for those students who don’t bother about time management.
So if you ask me, it’s not pre-boards’ scores but pre boards’ preparations that determine your performance in boards.
You however can predict how much you are going to score in boards by the marks of your pre boards. Usually, the papers set by schools are set on a higher difficulty level just to make students realize they need more practice. So if you are thorough with the paper of your pre-boards, chances are you’ll score quite well in boards.
And practicing not only your school’s pre-board question papers, but other schools’ questions papers can get you prepared perfectly for boards.
