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Octane Graphics Boards

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Revision as of 19:01, 27 July 2019 by Callahan (talk | contribs) (Added in-line IMPACT link)
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OCTANE/MXI Graphics Board


OCTANE/SI With Texture Memory Option Board


OCTANE/SI Graphics Board


OCTANE/SSI Graphics Board


V6 V8 V10 V12 ... V Pro graphics board


Option boards

OCTANE Personal Video Option Board


Replaces blank panel in slot D in the V Pro image.



IMPACT (sometimes spelled Impact) is a computer graphics architecture for Silicon Graphics computer workstations. IMPACT Graphics was developed in 1995 and was available as a high-end graphics option on workstations released during the mid-1990s. IMPACT graphics gives the workstation real-time 2D and 3D graphics rendering capability similar to that of even high-end PCs made well after IMPACT's introduction. IMPACT graphics systems consist of either one or two Geometry Engines and one or two Raster Engines in various configurations. IMPACT systems that included texture RAM (TRAM), such as the High Impact and Maximum Impact, also supported hardware-accelerated 3D texture mapping.

IMPACT graphics consists of five graphics subsystems: the Command Engine, Geometry Subsystem, Raster Engine, framebuffer and Display Subsystem. IMPACT Graphics can produce resolutions up to 1600 x 1200 pixels with 32-bit color and can also process unencoded NTSC and PAL analog television signals. Using custom Video Format Object (VFO) Files IMPACT graphics can also support resolutions of 1920x1080 (1080p) and 1920x1200 common in modern LCD monitors. IMPACT graphics systems' support for higher resolutions, refresh rates, and color depths are limited by their maximum pixel clock (160MHz) and limited video RAM.

IMPACT graphics subsystems come in three configurations for SGI Indigo2 IMPACT workstations: Solid IMPACT, High IMPACT, and Maximum IMPACT. The equivalent Octane Graphics Boards are referred to as SI (Solid Impact), SI+T (High Impact), and MXI (Maximum Impact). The Octane also introduced the SSI, which is a Maximum Impact system without TRAM. Later SGI Octane workstations used a similar configuration but with updated ASIC chips and are referred to as SE, SSE, and EMXI (E-series). IMPACT uses Rambus RDRAM for texture memory.

The IMPACT graphics architecture was superseded by SGI's VPro graphics architecture in 1997.

The three SGI Indigo2 IMPACT options, from least to most powerful, are:


Testing TRAMs

I have found that the best way to test any Impact with TRAM is with blender. Download it, install it, and test out some of the demos.

I would get High and MaxImpact boardsets that would pass IDE just fine, but would fail in blender at the customer site. That is when I started testing with blender.

Another test is to leave a spinning textured demo automatically rotating for more than 10 minutes (the tex_cube is a good candidate, as well as reflection mapping demos), and see if the Xserver crashes or not.

I wonder if somebody knows certain facts about these (seemingly famous) Xserver crashes from CFIFO timeouts in some IMPACT boards which appear to run fine (pass all diagnostics, textured demos run OK, etc...) It seems to work OK, but you leave an animated textured demo for some minutes, and you'll see the login screen.

Patterns on screen

>I'm having some serious problems with my video. I own an Indigo2 with
>HighImpact graphics. Nothing was the matter with it until some time ago
>it started showing regular patterns over the entire screen.

Been there, seen that. I am sorry to say but your HI graphics set is about to die. This is a typical symptom of Trams getting loose, the worst of all is the fact that this is quite likely to be the connection between memory chips and mainboard itself.

I lost 2 HI sets in my I2 in that way and I do know the reason: Power On - Off cycles are deadly for TRAMS because those sets tend to get very hot and thus cool-hot-cool-hot cycles take their toll.

When my first set died several years ago I took a time to resolder each and every leg of tram chips, it was hell of a job but did solve the problem.. for a short time...

Solution: For now, try to turn on your machine, leave it on for 2-3 hours and reboot, quite often the screen comes up okay but quite soon you will not be able to do that ether and will need to look for another gfx set.

No other part of my I2 ever failed but TRAMS are really sensitive, as I cannot leave my machine on all the time I finally given up on any gfx with trams and bought myself several SI sets and I am still on the first one, they are very robust :)

If you do need TRAMS, make sure you leave your machine on all the time.


General information

The VPro series (code name "Odyssey") is a a computer graphics architecture for SGI workstations. First released on the SGI Octane2, it was subsequently used on the SGI Fuel and SGI Tezro workstations. VPro provides some very advanced capabilities such as per-pixel lighting, also known as "phong shading", and 48-bit RGBA color.

There are currently four different VPro graphics board revisions, called: V6, V8, V10 and V12. The first series were the V6 and V8, with 32MB and 128MB of RAM respectively. The V10 and V12 had double the geometry performance of the older V6/V8, but were otherwise similar. The V6 and V10 can have up to 8MB RAM allocated to textures, while V8 and V12 can have up to 104MB RAM used for textures.

  • V10 and V12 have double the geometry performance of V6 and V8.
  • VPro graphics can be installed in older Octanes as long as the Octane has the proper power supply and Xbow (crossbar switch) revision.
  • V6 and V8 require Xbow rev. 1.3 or later, V10 and V12 require Xbow rev. 1.4 or later.


  • "OpenGL on a chip"™ technology
  • Hardware implementation of specular shading with per-pixel normal interpolation (through the SGIX_fragment_lighting extension)
  • 48-bit (12-bit per component) RGBA
  • 96-bit hardware-accelerated accumulation buffer for depth of field, full-scene anti-aliasing, motion blurs and other effects
  • texture memory capacity 8MB (V6, V10) or 104MB (V8, V12), total memory 32MB (V6, V10) or 128MB (V8, V12)
  • Perspective-correct textures and colors
  • High-performance hardware clipping
Option: Color: RAM: Max. Texture Memory Geometry Speed
V6 48bit RGBA 32MB 8MB Original GE speed
V8 48bit RGBA 128MB 104MB Original GE speed
V10 48bit RGBA 32MB 8MB 2X Faster GE speed
V12 48bit RGBA 128MB 104MB 2X Faster GE speed

EEPROM Information

See also this and this archived Nekochan forum topics.

EEPROM information
VPro Computer Part# EEPROM ID
V10 Fuel, old rev. 030_1725_00x ASTODYB
V10 Fuel, new rev. 030_1826_00x ASTODYV10
V12 Fuel 030_1726_00x ASTODY
V12 Fuel 030_1996_00x ASTODY
V12 Tezro 030_1884_00x ODY128B1_2
V12 Onyx350 InfinitePerformance 030_1909_00x ODY128B1_2

'AST' is for 'Asterix', the codename for Fuel. 'ODY' is short for Odyssey, the codename for VPro graphics.

Graphics subsystem

The VPro graphics subsystem consists of an SGI proprietary chip set and associated software. The chip set consists of the buzz ASIC, the pixel blaster and jammer (PB&J) ASIC, and associated SDRAM.

The buzz ASIC is a single-chip graphics pipeline. It operates at 251 MHz and contains on-chip SRAM. The buzz ASIC has three interfaces:

  • Host (16-bit, 400-MHz peer-to-peer XIO link)
  • SDRAM (The SDRAM is 32 MB (V6 or V10) or 128 MB (V8 or V12); the memory bus operates at half the speed of the buzz ASIC.)

All VPro boards support the OpenGL ARB imaging extensions, allowing for hardware acceleration of numerous imaging operations at real-time rates.

V6/V8 Pixel Clock Issues

The first generation of VPro boards (V6 & V8) have a design flaw that prohibits graphics modes in much of what might otherwise be considered the normal range for SGI desktop systems:

  • Modes in the 109-193MHz range cannot be selected at all on V6/V8.
  • Modes that are close to the lower end of that range (like 1280x1024_59/60) are only allowed at 8 bytes/pixel framebuffer size and even at that setting some people reported display problems (noise, flickering).

This limits the ability of the V6 and V8 to use a number of common display resolutions, a situation that can be at least partially over come with the use of reduced blanking. As an example, a CVT-generated [email protected] modeline without reduced blanking would have a Pixel Clock of 118.25MHz, which falls in the unusable 109-193MHz Pixel Clock range, while a modeline with reduced blanking would have a Pixel Clock of only 97.75MHz, which could be used by V6 or V8 graphics boards.

See Also

VPro Display Resolutions

This table was taken from's mirror of

Note: Additional resolutions are possible with custom Video Format Object (VFO) Files

Display Resolutions
(V6, V8, V10, V12)
Additional V8/V10/V12 Display Resolutions Additional V10/V12 Resolutions (3, 4)
1920x1080 at 30Hz interlaced 1920x1200 at 60Hz 1920x1200 at 72Hz (for DCD Option)
1600x1024 at 83Hz (1) 1280x1024 at 100Hz (quad stereo, 21" monitor only) 1920x1200 at 60Hz (for DCD Option)
1280x1024 at 100Hz (quad stereo, 21" monitor only) 1920x1080 at 30Hz interlaced 1920x1080 at 72Hz (for DCD Option)
1280x1024 at 96Hz) (2) 1600x1200 at 75Hz 1920x1080 at 60Hz (for DCD Option)
1280x960 at 30Hz interlaced 1600x1200 at 72Hz 1920x1035 at 30Hz interlaced
1280x720 at 72Hz 1600x1200 at 75Hz (for DCD Option)
1280x720 at 60Hz 1600x1200at 72Hz (for DCD Option)
1024x768 at 75Hz 1600x1200 at 60Hz
1024x768 at 60Hz 1600x1200 at 60Hz (for DCD Option)
800x600 at 60Hz 1600x1024 at 83Hz (for DCD Option)
768x576 at 25Hz interlaced 1600x1024 at 60Hz (for DCD Option)
640x480 at 60Hz 1280x1024 at 85Hz
640x486 at 30Hz interlaced 1280x1024 at 75Hz
1280x1024 at 72Hz
1280x1024 at 66Hz (for DCD Option)
1280x1024 at 60Hz
1600x1024 at 60Hz (for DCD Option)
1280x1024 at 30Hz
1280x960 at 30Hz interlaced (for DCD Option)
1280x492 at 120Hz stereo (3, 5)
1024x768 at 96Hz stereo
800x600 at 60Hz
768x576 at 25Hz interlaced
640x486 at 30Hz interlaced
640x480 at 60Hz

1: 24" monitor recommended for correct aspect ratio
2: 1280x1024 at 60Hz (available with 8-byte frame buffer depths, supports 4-bit per component RGBA, double-buffered with Z)
3: Support for some resolutions requires installation of IRIX 6.5.10 or higher
4: Resolutions designated for the Dual Channel Display (DCD) Option on V12 only are in skew mode for timing compatibility; while the two displays can have different resolutions, they must run at the same refresh rate
5: 1280x492 at 114Hz available with V6 and V8


The V6/V8 are a newer generation of graphics boards ("Vpro"). These are the same architecture as what ships in the current SGI Fuel workstations and what is used on the InfinitePerformance. They were also the standard on the OCTANE2 (circa Summer 2000) and available as upgrades on the OCTANE (which is what I assume you are interested in).

The MXE is derived from the series that started with the IMPACT on the SGI Indigo2 (Solid/High/Maximum IMPACT). MXI was the Maximum IMPACT which appeared in circa 1996. The MXE was the speed bumped MXI -- 40% average performance improvement.

Known drawbacks to the Vpro include comparability with older software and the V6/V8 Pixel Clock Issues that make some resolutions unavailable with the V6/V8 (note the V10/V12 fixed this issue). With each generation of graphics board after the GR2 (Elan/Extreme, etc), comparability with IrisGL has suffered. The new ATI-based cards (used in the UltimateVision) are beleived to offer no IrisGL comparability. Some use cases may also prefer the IMPACT XIO layout, although both VPro and SSI/MXI options leave two open XIO slots.

On the other hand, vector, polygon, etc (solid model) performance is much better on the Vpro than the IMPACT (2-5X maybe more in some cases). I am not aware of anything which is slower on the Vpro than the IMPACT. Vpro also offers more memory (32MB on the V6 and 128MB on the V8 compared to 27MB on the SSI/SSE/MXI/EMXU, excluding the MXI/EMXI's dedicated TRAM). This memory can be used to hold larger textures and/or allow larger framebuffers. VPro cards also use less power. For example, a system with a V8 installed uses about 30 watts less power than an EMXI during demanding 3D rendering.

Stereoscopic 3D (CrystalEyes) is very popular in molecular modeling among other fields. In that environment, the Vpro-line's (such as the V6) 1280x1024 @ 100Hz quad-buffered stereo resolution is very useful. One can keep the machine in that mode full time and applications can just pop in to stereo whenever they want -- no need to even flicker the screen. The MXI/MXE could switch back and forth between double-buffered 1280x1024 @ 76Hz and quad-buffered 1024x768 @ 96Hz but it wasn't as clean (the Solid/High IMPACT couldn't even do this). Among other things, applications had to know how to switch back and forth. The problem now is that some applications are so used to switching modes that they don't know that it isn't needed on the Vpro.

Vpro also has some other features like deeper visuals including some with 12-bit instead of 8-bit per component precision, new extensions, accumulation buffer (software on V6, hardware on V8), etc. The most useful features for people I work with was speed and stereo. I am sure for other people, the larger texture memory (especially V8), 12-bit precision, or extensions are even more important.

Using VPro and IMPACT Graphics Simultaneously

It is possible to use both VPro and SI/SE graphics simultaneously to support dual-head operations. However, these configurations only support OpenGL rendering on one of the monitors (the VPro is the obvious choice due to its much faster all-around performance), which makes it useless to add TRAM to the SI/SE. While supported in software and capable of better 2D performance, SSI/SSE/MXI/EMXI cards cannot fit into the VPro's unique XIO carrier.

VPro/IMPACT dual-head operations were first demonstrated in 2005 and have been recently explored further.

> I've got an Octane2 with V6 graphics I'd really love to throw a second 
> head in, but without shelling out for the special dual VPro XIO carrier 
> and an extra VPro head.  Looking at the Octane2 XIO carrier there are 2 
> standard XIO slots below the VPro graphics pipe.  Having put together 
> multiheaded IMPACTSR Octanes this makes me curious whether I can put one 
> of my spare SI boards in these slots.
Sure, you can put it in, *BUT*...

You can only *use* one of those two, though, as inst/swmgr will
force you to pick one set of binaries/libraries/kernel drivers - one
is for VPro, the other for MardiGras/IMPACT.

See Also

Photo Gallery