Riser Card Directional Orientation only applies to single and multi-slot right angle riser cards. The orientation of a right angle riser card determines what direction the peripheral card will face, whether is be towards the cpu or away from the cpu in some cases. For customers using right angle riser cards, they can either choose from A-Side Right Placement risers or B-Side Left Placement riser cards.

A-Side Right Placement is where the peripheral card plugs into the riser card and is facing the right side (viewed from the front of the motherboard) with the solder side down. Below is an photo of a A-side riser card being used on a motherboard, when a card is plugged in it will be hanging over the A-side of the riser card.

A-Side Riser Card with 5V slot (PCITX4-1-A5/B3)

B-Side Left Placement is where the peripheral card plugs into the riser card and is facing the left side (viewed from the front of the motherboard) with the solder side up. Below is an photo of a A-side riser card being used on a motherboard, when a card is plugged in it will be hanging over the B-side of the riser card.

B-Side Riser Card with 5V slot (PCITX4-1-B5/A3)

Some riser cards have interchangeable orientations but with different voltages for each direction. For example the PCITX4-1-B5/A3, after the model number, "B5" means when this riser is plugged into the B-Side Left Placement it can support 5V cards, "A3" means when it is plugged into the A-Side Right Placement it can support 3.3V cards. Both orientations and voltages support universal voltage cards that are keyed for both 5V and 3.3V cards.

This riser card also comes in a reverse orientation as well, the part number is PCITX4-1-A5/B3, after the model number, "A5" means when this riser is plugged into the A-Side Right Placement it can support 5V cards, "B3" means when it is plugged into the B-Side Right Placement it can support 3.3V cards.