Asus DSEB-D16/SAS - Manual (Page 25)

ASUS DSEB-D16 Series 2-5
4. Press the lower spring clips inward,
then insert to the lower CPU
heatsink holes until they snap in
place.
5. If you installed a second CPU,
repeat steps 2 to 4 to install the
CEK spring to the CPU2 heatsink
holes.
The CEK springs appear as shown
when installed.
CEK spring screw hole
3. Press the upper spring hooks
inward, then insert to the upper
CPU heatsink holes until they snap
in place.