CalDigit RAID Card - Manual (Page 11)

11 A. MacPro
CPU Cover
Pull from here.
Fan module
(b) (8 Core Mac Pro) Remove the CPU cover by pulling the bottom edge of
the CPU cover slightly toward you.
1.8 Remove the fan module
(a) (4 Core Mac Pro) Remove the fan module screw and take out the fan
module.
(b) (8 Core Mac Pro) Remove the fan module screws (one at the upper-right
rear corner and a second at the lower- right front corner and take out
the fan module.)