Upgrade SGI O2 from R5-7k to 10-12k

It is possible to upgrade an SGI O2 from R5000/7000 CPUs to R10000/12000 CPUs. The process takes about an hour and requires some specific parts.


  • An SGI O2 with the latest PROM (4.18) and preferred 6.5.22 or later installed.
  • A chassis that will accept an R10K/R12K CPU module. There are essentially 3 breeds of chassis out there, R5K only with no removable drive divider, R5K with removable drive divider and finally an R10K/R12K chassis where the divider is already missing.
  • An R10k or 12k PIMM (Processor/CPU module) and the 4-screws and tray it sits in.
  • The three screws used to secure the plastic tray to the motherboard (one screw from the underside) and the motherboard tray (two screws, slightly longer from the top). These are machine screws and cannot be reused from an R5000 module.
  • A suitable motherboard tray, this has different side and rear panels to accommodate the gap where the extra drive would have been in the R5K chassis. It also has a slightly different backplate which has an extra screw fitting.
  • CPU stand off connectors. This is where it gets really tricky as these are not readily obtainable. These are probably the hardest to come by of the whole upgrade.
  • PCI Riser for R10000/12000 models. The PCI riser pcb contains a little Dallas chip with the O2’s hardware address on it, hence it cannot be omitted.

Every other piece of the O2 can be reused.


Step 1. Unplug the O2 and remove the power supply. Do not skip this step, as it will fry the chassis frontplane and other pieces.

Step 2. If the O2 chassis has a drive divider panel, unscrew the two screws for it and remove it by sliding it out of the unit.

Step 3. Remove the rear PSU cover and black top cover, followed by the rear components : Power supply, drives, AV module and system board tray. Next, on the top of the unit unscrew the two outer skin retaining screws that hold the skin to the optical drive outer tray / cover. Remove the blue (purple for O2+) outer skin by lifting it up and place to one side, out of harms way.

Step 4. Remove the optical drive holder by unscrewing the two screws near the front of the metal enclosure. Slide the drive and enclosure forward to unplug the power cable and SCSI ribbon.

Step 5. Remove the bottom skirt. Turn the machine over and stand it on its head. Make sure to unplug the speaker cable from the frontplane connector before removing the skirt. The bottom panel (or skirt) is held on with two black indent tabs and a series of plastic prongs that fit into the chassis. The two indent tabs simply prevent the skirt from sliding sideways and keeps the tabs engaged in the chassis.

Step 6. To remove the frontplane, take off the shiny metal cover / faceplate. Have a look at the corners of the cover, there are tabs with round ridged protrusions holding this to the chassis, simply push these in slightly and it should be able to slide out slowly. To stop the faceplate / cover from bending, work loose all the corners then pull it away a bit at a time. Once exposed, unscrew the frontplane from the chassis.

Step 7. Remove PCI tray and riser assembly. Press the lever above the CPU module down and it should slide out with some gentle wiggles.

Step 8. Remove the RAM modules by pressing both sides of the tabs down completely, and then pulling the modules out. Remove the CPU carrier by removing the retaining screws on the plastic, the CPU should come off with it. The CPU and carrier lifts off quite easily, do not twist while pulling the module.

Step 9. Remove the two R5K CPU stand offs (little white plastic risers) using a very small flat screw driver (Such a jewelers or eyeglass screwdriver) or blade edge. The stand-offs clip onto the motherboard connector and can be pried off where they clip on to the motherboard quite easily.

Step 10. Next up, remove the rear IO panel screws that hold the motherboard to the backplate and tray. The motherboard slides out for an inch or so, and it will lift up and out at a bit of an angle. (If an FP1600 adapter card is installed, remove it prior to attempting this.) Replace the backplate. The backplate is held on with a few screws and IO hex nut screws, it’s a simple swap. While the motherboard is out, it's a good opportunity to clean the tray and board.

Step 11. Slide the motherboard back in and screw the metal backplate to the tray, it’s reverse procedure again. Now fit the R10K/R12k risers, they can only go on in one direction / orientation, do not force them on. If they don’t want to slide on easily, they are probably oriented the wrong way.

Step 12. Replace the FP adapter or other accessory boards.

Step 13. Next up fit the R10K/R12K CPU PIMM carrier to the motherboard and screw in the top two screws. Turn the motherboard and tray over and screw in the slightly shorter screw from the bottom. Ensure all three screws are fitted.

Step 14. Turn the assembly back over again and fit the CPU to the carrier tray, gently push the CPU onto the little riser connectors, once again do not twist while applying light pressure. The module screws in with 4 machine screws. Make sure the CPU is properly seated on the risers, otherwise the boot process will fail.

Step 15. Fit The R10K/R12K PCI riser card and PCI tray, followed by RAM modules.

The motherboard is now prepared at this stage.

Step 16. Reinstall the power supply, motherboard, A/V board and boot drive. Test the machine. If the machine boots with a solid red light, remove the motherboard and reseat the CPU module, applying gentle pressure to fully seat it.

Step 17. Double check the hinv and env variables in command monitor, ensure the boot drive is using disk(2)