Although the Vision HT 420D isn't designed for gaming as an HTPC, it would be nice if casual gaming were possible even if we realize Intel's HD Graphics 4600 can't handle intense gaming.
At just 1280x800 and medium quality settings in Metro: Last Light, the Vision HT 420D rendered just 11fps, by far the slowest system tested. Enabling dual-channel memory did improve performance by 45% but at 16fps the game is still far from playable.
Lowering the graphic quality to low in Tomb Raider allowed the Vision HT 420D to average 30fps at 1280x800, which is borderline playable at this low resolution. Adding another memory module for dual-channel mode increased the frame rate by 29% to a more respectable 38.5fps.
At medium quality in BioShock Infinite, Asrock's new HTPC averaged 17.3fps while dual-channel memory increased that 47% to 25.4fps.