Origin 300


The SGI Origin 300 is a rack-mounted, mid range server sold by Silicon Graphics from 2001 to 2004. The 300 was offered in two to 32 processor configurations, at speeds ranging from 400 to 600MHz over the lifetime of the model. The Origin 300 is not a member of the later Chimera family, though it shares superficial and functional similarities with it. Its closest relative is the SGI Fuel.


Each CPU brick has two PCI slots across a PCI bus. All compute bricks are equipped with an IO8 BaseIO card with SCSI interfaces for two internal disks, an external SCSI port, and a twisted pair Ethernet connection.


Each brick can take dual or quad CPU configurations. The CPUs are attached to the main board, thus a configuration upgrade requires removal of the entire main board.

CPU Configurations
CPU Cache Dual (MHz) Quad (MHz)
2MB 500 500
4MB 600 600


On introduction SGI claimed an industry-leading 3.2 GByte-per-second processor to memory bandwidth, and half that to the graphics subsystem. The DIMMS used are compatible with those used in the Origin 3000, Fuel, Origin/Onyx350. and the Tezro. There are a total of eight slots, organized into two banks of two slots. This results in a memory capacity from 512 MB to 4 GB total system memory.

All DIMMS for the Origin 300 use Double Data Rate (DDR) synchronous dynamic random-access memory (SDRAM), at the lowest level organized into banks of two DIMMs each - memory may only be added or removed from the system in pairs of two DIMMs. Both DIMMs within a bank must be of the same density, however two different banks may hold different density DIMMs from each other.

SGI produced DIMMs with capacities of 256MB to 1GB, using DRAM chips with densities of either 128 Mbits or 256 Mbits. All DIMMs include directory memory to support cache coherence between local and remote memory, which remains unused in the Fuel. Memory was generally marketed in kits of two DIMMs, where the capacity of the kit would be given as 512MB, 1GB, or 2GB.


The IO8 card provides SCSI backplane support, and a 100Mbit Ethernet port. Two PCI-X slots can provide additional cards, such as network cards, SCSI cards, Firewire, extra audio and more.

NUMAlink is a high-speed low-latency switched fabric computer bus used as a shared memory computer cluster processor interconnection in Silicon Graphics computer systems. The Origin 300 leverages NUMALink heavily to link bricks together. Each unit has a NUMALink and an XIO port, used to link various subsystems together.

Multiple bricks are co-ordinated at startup time via an L2 Controller which communicates to the bricks via USB ports. The L2 Controller is an external PowerPC Linux unit with console, USB, modem and ethernet ports.

A system consists of up to eight CPU "bricks" (2 rackmount units high each) with up to four CPUs in each brick, giving a maximum of 32 CPUs. CPU bricks are connected together via NUMAlink3 cables going to a central NUMAlink Router (or NUMAlink Module) which is another 2U rackmounted unit.


The Origin 300 has a front bay for two U160 SCSI drives. It uses proprietary sleds for this purpose.

These sleds are standard off-the-shelf parts used by a number of high-volume server manufacturers, but were apparently only used by SGI on the Origin and Onyx 300 models.

Often Origin 300 systems will be split up and the individual bricks sold to different buyers. While many of these bricks never had hard drives installed, SGI did install sleds with baffles to maintain airflow. This is good news for buyers, as the plastic baffles can be removed and hard drives installed in their place.

The units typically have a sticker on the front of the sled showing the identifier "Assy A06447-00x" where the "-00x" may end in any digit. The second line of the label includes what may be an additional part number ("203368", as seen in the thumbnail image to the right) and a manufacturing code of some kind. It is unclear whether the manufacturing code indicates time of production, plant, batch run, or something else entirely.

However the assembly number from SGI units has not always been useful when searching for replacement parts in the Internet. It was suggested that Intel part number 746797-001 may be the same OEM part.

The 746797-001 part number is referenced in some sources as being used on Intel's SR1200/2200 and ISP2150G servers (black bezel). However images from some eBay auctions appear more similar to the Origin 350-style drive sled, and indeed the Intel product guide for the SR1200 has diagrams showing a unit more similar to that used in the Origin 350.

Onyx 300

An Onyx 300 is an Origin 300 NUMALinked to a G-Brick.

Hardware Problems

The main issue affecting these units is invalid serial numbers, which can be fixed using another brick, an L2 controller, or an L2 emulator.

Operating System Support

The Origin 300 was supported beginning with IRIX 6.5.14, and is supported through IRIX 6.5.30