Hmm. I make it ~60 times per minute absolute minimum, but it's going to be even more than that:

According to the FAQ, the sleds dimenions are 2"x7.2"x6.8" = ~98 cubic inches. (The dimensions are all 'max' dimensions, so the players dimension would include more errors because of the fascia being wider/taller than everything else, hence the use of the sleds dimensions.)

1 cubic foot is 1728 cubic inches. Therefore 3.5cfm is 6048 cubic inches per minute.

But, a significant percentage of the empegs volume is filled with miscellania, such as motherboard, display board, hard drives etc..If we estimated this percentage to be 40%, then that leaves approximately 60 cubic inches of air.

So we are probably looking at a figure nearer 100 times per minute.