The Super Grafx was an advanced version of the PC engine which NEC released prio to releasing the Duo all-in-one variants of the PC Engine and CD. If features more video chips and RAM among other optimizations. However, there were only 7 games released which benefit from these advanced possibilities. It could be connected to the Super CD-Rom2 unit, although no CD-games using the advanced technology of the Super Grafx were ever released. As the system was released shortly before the Duo, it was considered as “old” quite soon and therefore does not has much historical relevance.