Just near PCI-Express x16 interface, there is a mini PCI-Express x1 slot, that technically can take a mini-PCIe SSD or any other PCI-E device. While Galaxy is notorious for coming up with the most wacky yet intriguing designs the most plausible utility we see of this mini-PCIe slot is perhaps an optional addon board with a smaller GPU for processing PhysX, or a mini-PCIe TV tuner (notebook grade). Aside from this, connectors include a DVI, a DisplayPort, a mini-USB (female), a switch, and a 10-pin header right behind it.
Source: TechPowerUp