The SGI Indigo²

 General Information


The purple Indigo² is the newer version which normally has a R10000 processor and impact graphics. The first generation Indigo²s had a teal case and used a completely different graphics architecture and older processors. See my other Indigo² for further information.

Graphics Options

The first Indigo²s graphic options still based on the "Express Graphic" architecture from the original Indigos. But the Indigo² has a faster bus system plus you can have more geometry engines, so the Indigo² graphic options are faster than the Indigo options.

Option GEs REs
XL 0 1
XZ 2 1
XZ Elan 4 1
Extreme 8 2
RE: Raster Engine  GE: Geometry Engines
  • Command Processor: HQ2
  • Geometry Engine: GE7
  • Raster Engine: RE3


With the introduction of the purple Indigo²s a new graphic architecture was introduced: The Solid Impact architecture. It was the first desktop graphic system from SGI that could offer texture mapping acceleration (but you need at least the HighImpact option).

Option GEs REs Texture
SolidImpact 1 1 none
HighImpact 1 1 1
HighImpact AA 2 1 1
MaximumImpact 2 2 2
RE: Raster Engine  GE: Geometry Engines
  Texture: Texture Modules
  • Command Processor: HQ3
  • Geometry Engine: GE11
  • Raster Engine: RE4


The graphic options are connected to the system via the backplane which has standard EISA slots plus proprietary GIO64 slots which are designed for the graphic options. Note that you cannot easily upgrade every teal Indigo² to SolidImpact graphic, because the backplane changed a bit. You can easily tell, which backplane you have: The original old backplane for the Express options have 4 EISA slots and 3 GIO64 slots, whereas the Impact have 3 EISA slots and 4 GIO64 slots.

Processor Options

Processor Speed Cache Board
R4000SC 100 Mhz L1: 8kB+8kB L2: 1MB IP22
R4400SC 150 Mhz
200 Mhz
L1: 16kB+16kB L2: 1MB IP22
R4400SC 175 Mhz
200 Mhz
250 Mhz
L1: 16kB+16kB L2: 2MB IP22
R4600SC 133 Mhz L1: 16kB+16kB L2: 512kB IP22
R8000SC 75 Mhz L2: 2MB IP26
R10000SC 175 Mhz
195 Mhz
L1: 32kB+32kB L2: 1MB IP28

As you can see, different processor familiys (R4x00, R8000 and R10000) require different mainboards, thus an upgrade is cheap only in rare cases, when you stay within the same CPU family.

It is also possible to tune an Indigo² to use a 200MHz R10000.


As the Indigo R4000 and the Indy, the Indy uses standard 72pin PS/2 FPM memory with 36Bit and parity, so it should not be a big deal to find some upgrades in the second hand market. You can use SIMMs up to 32MB per module for IP22 and IP26 boards and modules up to 64MB per module for the newer IP28 boards (Some people also confirm that you can even use modules up to 128MB to get 1GB of RAM, but this is not officially supported by SGI - on the other hand Indigo²s aren't supported any more at all). In contrast to many PCs, you have to insert modules in groups of four and the Indigo² has 12 slots in total.

The Systembus

The Indigo² has a bus called GIO64 which uses much larger boards than the GIO32 boards used in Indys and Indigos. As can be noted from the name, it is 64 bits wide instead of 32 bits wide. The GIO64 bus has a theoratical maximum bandwidth of 266Mb/s.

Boards for this bus are roughly the same size as EISA boards since both GIO64 boards and EISA boards live in the same backplane. The I/O panel space for a GIO64 board is identical to that for an EISA board. The outline of the board does differ from a standard EISA board however.

The EISA bus used in the Indigo² is the same bus used by PC compatibles. EISA bus boards share four physical slots with GIO64 boards in the Indigo2. Since the EISA bus is a superset of the ISA bus, ISA boards will also fit into the Indigo2.

Note that there are two different versions of the backplane and you need the newer version with only three EISA slots for all Impact graphics family cards.


There are several (five to be exact) different power-supplies available for the Indigo²:

Part Number Description
9430814 Suitable for Extreme, XZ and XL graphics on R4400 and R8000 machines.
060-8001-xxx Suitable for single-head (Solid, High or Max) IMPACT graphics and
dual-head Solid/Solid IMPACT graphics on R4400 machines. Can also
be used in place of 9430814.
060-0021-xxx Suitable for dual-head (Max/Solid, High/High or High/Solid) IMPACT
graphics on R4400 machines. Can also be used in place of 9430814
or 060-8001-xxx.
060-8002-xxx Suitable for single-head IMPACT graphics on R10000 machines.
060-0027-xxx Suitable for dual-head IMPACT graphics on R10000 machines. Can
also be used in place of 060-8002-xxx.


An Indigo² just needs a standard PS/2 keyboard and mouse (of course there are special gray keyboards and mice from SGI available) and has standard sound input/output connectors plus a 10MBit ethernet connector. The only item you have to care about is the monitor: Indigo²s do have - as most SGI systems - a 13W3 monitor connector and use "sync-on-green" - although most modern PC Monitors support this method, you should assure that it really does by reading the manual before plugging it to an Indigo².

Video Options

  • Video Creator
    VideoCreator is available as an optional external or internal board for video output in either compressed or uncompressed format (SCSI or VME).
  • Indigo²2 Video
    A low-end video option which still includes video input and output (only for XL, XZ and Extreme).
  • Cosmo Compress
    Adds hardware compression/decompression functionality to systems and can be added to Indigo² Video systems using an external connection.
  • Galileo Video
    High-end video option for systems with Express graphics on the Indigo² .
  • Indigo² Video for Impact
    A low-end video option which still includes video input and output (same as above, but for Impact graphics).
  • Indigo² Impact Video
    Broadcast quality video option with (only!) digital input and output (for Impact systems only).
  • Indigo² Color Space Conversion
    Optional card vor Indigo² Impact Video that does conversion between YUVA and RGB. It allows to use video as textures.
  • Indigo² Impact Compress
    Motion JPEG option card for standalone or use with Indigo² Impact Video. Composite and S-Video in-/output.

Other Options

  • Phobos G160 GIO network interface (10/100mbit)
  • Phobos E100 EISA network interface (10/100mbit)
  • FDDI single/dual attach GIO cards
  • Fibrechannel GIO adapter
  • HIPPI GIO network interface
  • bit3 VME expansion card
  • Presenter adapter

My Indigo²s

I own two Indigo²s: A purple one and a teal one.