ASUS has even said that with the latest GPU drivers from AMD and NVIDIA, the B250 Mining Expert motherboard will support up to 8 x GPUs in multi-GPU mode. AMD has teased a new driver for later this year which will support 19 graphics cards later this year, but until then you can run 8 x Radeon and 8 x GeForce graphics cards and still hit 16 x graphics cards... a massive achievement.
Via: TweakTown