SGI: Hardware

I just swapped my R5k 180 MHz to a R5200 300MHz and it seems this CPU does not support 1GB RAM. With the old CPU I can use all of the 1GB RAM, but with the new one I can only use 768MB.

I have a PROM V4.18, I think.

Does anyone know if this is normal and maybe how it can be fixed?

The hinv in this post would certainly suggest you can: viewtopic.php?t=16727969

That´s interesting. I have 2 O2´s and in both I get only 768MB of 1024MB installed when I insert the R5200 CPU. One Board is newer than the other and for this newer board I don´t know the PROM version, but the older board has a PROM V4.18.

And as I said, it´s the same for both boards, with the R5k CPU I get the whole 1024MB RAM and with the R5200 CPU I only get 768MB.

Does anyone have an idea what I can do about it?

FlasBurn wrote: Does anyone have an idea what I can do about it?

It might be your system board or PROM version needs updating (my guess is PROM). One of my O2's is basically an O2+, just with blue skins. 1GB RAM, RM7000 350MHz, MD-RAID1 w/ 2x 73GB drives, runs Linux. PROM is 4.18, and the system board is one of the later revisions.

I hope that I can do more tests at the weekend. I´ve got an older board with PROM 4.18 and a newer board with PROM 4.14 or 4.15. Problem with the newer board is, I would need to get the board out of the "tray". Is this possible?

FlasBurn wrote: I hope that I can do more tests at the weekend. I´ve got an older board with PROM 4.18 and a newer board with PROM 4.14 or 4.15. Problem with the newer board is, I would need to get the board out of the "tray". Is this possible?

Yup, entirely possible. More tedious and tricky than difficult, though. In addition to the various screws you have to undo, you also have to unscrew the mounting screws on the rear-facing ports as well (and put them back when re-mounting the board).