Boards really don't take up that much server space.
Consider this, the thread itself is just a page, every thread on the board is the same page (showthread.php), same with each forum - just one page, the query after the thread page address (&threadis=202916) or forum address page (&forumid=12) tells the server which thread posts or forum details to collect from the database.
I own a forum with a larger member base than this one (close to 100,000 members) which holds close to 10 million posts and it's just touching 10gb in database size. The actual forum pages on the server don't even come to 5mb even when the images are included. Neither of those numbers are even close to maxing the 2, 200gb hard-drives.
Scores pages are the same. They'll just be a table on a database and each player is just a row in that table. 5,000 rows in a database table is squat.