When I say HD playback in the late nineties I mean in high end vfx production houses, 1920x1080, or 2048x1024 sometimes. Lesser resolutions could be played back by less exotic hardware than SGIs at the time. First time I saw real time uncompressed HD playback in a studio was Sony in 1997 and that was on custom hardware. We still had dailies on film back then, so getting called into a viewing on the special exotic playback machine with the VFX supe was a big deal rather than waiting to see it on film the following morning.
The published specs, especially in earlier docs and what ended up being possible with Impact graphics may not be the same thing. It may take some custom resolutions being added to the config, but I am using pretty ancient memories at this point. But I do seem to recall at least later EMXI on Octane doing 1920x1080, maybe only 1080I? Again, I could be wrong, but I seem to recall that. I seem to recall the Max with TRAM supporting resolutions that non 4mb TRAM and especially Solid Impact couldn't? At least out of the box my SI here is only offering 1600x1200@57. I will try that out, but 57hz? We'll see how my converters deal with that.
https://wiki.preterhuman.net/Video_Forma...VFO)_Files
"Limitations and Workarounds
All systems:
When using a pixel-based (in contrast to a time-based) .vfs input, the total blank lines (HorizontalTotal-HorizontalDisplay) must be divisible by 8.
IMPACT:
Pixel clock cannot exceed 160MHz.
Framebuffer usage (total active pixels*bits per pixel) cannot exceed 13.5MB (1RSS) or 27MB (2RSS).
Some users have noted visual artifacts on IMPACT systems with modern LCDs using high resolutions (such as 1920x1080) and the monitor's native EDID resolution. These artifacts have been reduced or eliminated by incrementally increasing the blanking in the custom .vfs file."
Pretty sure my Extron will do 1920x1080P@60, May be a matter of what the Geffin DVI converter can read? Finding a 1920x1080 mode it likes. Granted even if I can get 1920x1080 running on an Impact, it may hurt performance considerably? But of course I have to try. I never got a chance to use IRIX at higher than 1280x1024 back when I used them professionally, and only years after the switch to Linux did 1920x1080 become a common resolution in VFX houses. But in the last years of using SGIs I did want a HD 16:9 monitor pretty bad. Seeing the grand GDM-FW9011 in the playback and Flame suites, so generally Onyxes and the like was damn sexy and I always wanted to work on that kind of res. I do have an Octane2 with V6 graphics in my distant ancient storage. Looking at the process to compile the config files on Impact's is daunting. Seems compiling for VPro is a lot simpler.
Also from that link:
Compiling a Custom .vfo/.sdb file
Creating and using a custom vfo file for an SGI computer is a multi-step process.
Build a plain text input file, customarily with the .vfs extension, using the EDID for the monitor in question.
Compile the .vfs file using the vfc command and the appropriate pre-compiler options. Some hardware, such as IMPACT graphics on Octane and Indigo2 systems, require long pre-compiler option strings.
Name the output file appropriately. VPro systems use the .vfo extension, while IMPACT systems use the .sdb extension.
Place the file in the appropriate subfolder of /usr/gfx/ucode/, such as /usr/gfx/ucode/ODSY/vof/ (for VPRO) or /usr/gfx/ucode/MGRAS/vof/2RSS for Max Impact Indigo2 and Octane systems, as well as Octane SSI/SSE systems. This will enable selecting the new resolution using the GUI Display Options tool.
VFC Command and Precompiler Options
Using VFC to create a custom .sdb file for IMPACT graphics requires setting many pre-compiler options. An example VFC command is:
vfc -a ascii=vfsname.info -c board=/usr/gfx/ucode/vfc/rules/mgras.def,chip=/usr/gfx/ucode/vfc/rules/mgras_vc3.def -p "-DRSSCOUNT=2" -p "-DDB32=1" -p "-DINTERLACED=0" -p "-DSTEREO_FMT=0" -p "-DOPTIONS=0" -p "-DZBUF=1" -p "-DVERT_SERRATION=0" -o vfsname.sdb vfsname.vfs
A breakdown of the VFC and precompiler options for a MGRAS system:
"-a ascii=vfsname.info": Writes a summary with key resolution and frame data to the file vfsname.info
"-c board ...,chip ...":specifies the appropriate files for IMPACT/MGRAS graphics.
"-p": Specifies a command passed to the pre-compiler
"-DRSSCOUNT=2": Specifies the number of raster engines. Octane SSI/SSE/MXI/EMXI and Indigo2 Max Impact have two raster engines. Other Impact boards have one (Octane SI/SE and Indigo2 Solid and High Impact)
"-DDB32": Set to 1 to enable large double buffered visuals
"-DINTERLACED=0": Non-interlaced
"-DSTEREO_FMT=0": Not stereo (e.g. not for use with 3D glasses)
"-DOPTIONS=0": There are three "options" (0,1,2) that change how the pre-compiler computes blanking periods and possibly other things. If you understand what this does exactly, please update this wiki. Options 0 and 2 seem to work well with reduced blanking LCD files, while option 1 often does not.
"-DZBUF=1": Enable Z-buffered visuals
"-DVERT_SERRATION=0": A serrated vertical sync pulse may be required for some interlaced modes
"-o vfsname.sdb": Name of output
"vfsname.vfs": Input
Using VFC to create a .vfo file for VPro systems is more straightforward. An example command for VPro/ODYSSEY boards is:
vfc -a ascii=vfsname.info -c chip=/usr/gfx/ucode/vfc/rules/VPro_Chip.def,board=/usr/gfx/ucode/vfc/rules/VPro_Board.def -o vfsname.vfo vfsname.vfs
A breakdown of the VFC options for a VPro system:
"-a ascii=vfsname.info": Writes a summary with key resolution and frame data to the file vfsname.info
"-c board ...,chip ...":specifies the appropriate files for VPro graphics. Note this is case-sensitive!
"-o vfsname.sdb": Name of output
"vfsname.vfs": Input
NEED -> 
