Rounding off the Altix line at the lower end, the Altix 330 starts with 2 processors in a 1U enclosure. Scaling up to 16 processors, then taking 9U of rack space.

Altix 330 page at SGI

Being the entry system of the Altix line - expandable up to 512 processors - the Altix 330 sets new standards for space economy. Each system module houses two Itanium 2 processors, up to 16 gigabyes of memory, two SATA2 or SAS disks, a DVD-ROM and a PCI-X slot. For more PCI slots an expansion module can be attached, adding six additional slots. Two system modules may be connected by a simple cable to form a shared-memory system with four processors. With the optional router up to eight modules can be connected. NUMAlink 4 cables connect the system modules with a datarate of up to 6.4 GigaBit per second.