Most EDO will work, but it's not used on any of the x500 or x600 motherboards from Apple.
The reason that the speed matters is that there were plenty of models which drove the memory bus at speeds around 40 to 45 MHz. When running the bus at 50 MHz, especially with interleaving, the speeds of the memory mattered more. Since there were lots of DIMMs around from the pre-50 MHz bus days, it can get somewhat confusing.
If a machine only boots part of the time with certain memory installed, I'd recommend putting in those DIMMs one at a time to see if it happens with any pattern. If it's caused by one or two DIMMs specifically, exchange them. I believe that Sonnet has a lifetime warranty on their memory. OWC does, as do many places, although you really need to make sure you keep the receipt for some of the places.
I remember having a problem about ten years ago when trying to figure out which DIMM out of twelve in a fully populated 9600 was bad. The machine only crashed once every few days and it was colocated. Talk about a nightmare!
The reason that the speed matters is that there were plenty of models which drove the memory bus at speeds around 40 to 45 MHz. When running the bus at 50 MHz, especially with interleaving, the speeds of the memory mattered more. Since there were lots of DIMMs around from the pre-50 MHz bus days, it can get somewhat confusing.
If a machine only boots part of the time with certain memory installed, I'd recommend putting in those DIMMs one at a time to see if it happens with any pattern. If it's caused by one or two DIMMs specifically, exchange them. I believe that Sonnet has a lifetime warranty on their memory. OWC does, as do many places, although you really need to make sure you keep the receipt for some of the places.
I remember having a problem about ten years ago when trying to figure out which DIMM out of twelve in a fully populated 9600 was bad. The machine only crashed once every few days and it was colocated. Talk about a nightmare!