Since nForce 590 SLI chipset supports SLI technology, this motherboard has two x16 PCI Express slots, each one truly running at x16 transfer rate. This motherboard has one x1 PCI Express slot and three standard PCI slots.
On the storage side, this motherboard has a lot of HDD ports. The south bridge used by nForce 590 SLI brings one ATA-133 port and six SATA-300 ports, supporting NCQ, RAID0, RAID1, RAID0+1, RAID5 and JBOD. The additional SiliconImage SiI3132 chip brings two extra SATA-300 ports, supporting NCQ, RAID (0, 1 and JBOD) and Port Multiplier at one of them, which is strategically soldered on the external side (back panel) of the motherboard. Since this chip was placed near the back panel of the motherboard, the extra internal SATA-300 port is located in an unusual place, at the back of the motherboard, between the back panel and the memory sockets (see Figure 7).
In Figure 8, you can see this motherboard back panel. You will find the external SATA-300 port multiplier located below the FireWire port, in red.
Port multiplier is a technology targeted to external hard disk drives, allowing you to connect up to five Serial ATA hard disk drives to a single SATA-300 port. In order to use five SATA HDDs on this port you need an external port multiplier bridge, which is an external device sold separately. The hard disks are connected to this device, while this device is connected to this port multiplier port, which, in turn, is internally connected to one of the SATA ports controlled by the SiliconImage chip on the motherboard.