My Apollo 12060/66 MC68060RC50A with 64MB ram, scsi wich i clocked to 80Mhz started to have mem problem after about 5years.
I found that it would only works if mem simms were swaped around it would work even tho they were the same make.
Then that stoped & i had to mix the makes of simms,that worked for a while.
I bought a Mediator & voodoo3 but found when i used the voodoo3 driver in MMU mode the gfx would corrupt, but everything else that used the MMU worked just fine.
When useing the voodoo3 with vblank interrupt the amiga sortof lockup after a few clickings on progs or draws.
I could not move the mouse pointer or use keyboard,music & movies that was running would still play.
Then the mem went totally only 32megs showing of the 64 that i had pluged in.
Swaped the simms then for some strange reason it showed that i had 128MB's wish is not possible.
Had to see if i could get the 1260 fixed.
I went back to Analogic & they said its nuked.
I said do you have anymore 1260 they said yes one left but it was only a 50Mhz version :-(
I said swap my MC68060RC50A from the old to the new to see if it was just the board that had nuked but not the cpu & lucky for me the cpu was fine :-).
It seems the old board was get worse over time as now all the problems i had with the mediator the voodoo3 has gone.
The MC68060RC50A is near impossible to get hold of now & i have seen many 060 cards sold as 66 wich dont have the MC68060RC50A id on the chip or show up as Rev 5 in some software that can show the revision number.
If its not MC68060RC50A or shows up as Rev 5 its not a true 66. & you can forget about running at at anything past 66Mhz.
This MC68060RC50A as been running now at 80Mhz for 7-8 years now.