Asus M3A78-EH - Manual (Page 21)

ASUS M3A78-EH 1-9
Do not overtighten the screws! Doing so can damage the motherboard.
1.5.2 Placement direction
When installing the motherboard, make sure that you place it into the chassis in
the correct orientation. The edge with external ports goes to the rear part of the
chassis as indicated in the image below.
1.5.3 Screw holes
Place six (6) screws into the holes indicated by circles to secure the
motherboard to the chassis.
R
M3A78-EH
Place this side towards
the rear of the chassis