JFYI, with the 610 series, you can't interleave RAM SIMMs because of the way they arranged the banks. It has half the SIMM slots, and rather than just leaving off the top 2 SIMMs, they've split things up so every other bank will be empty, preventing any interleaving of the SIMM slots. 8mb soldered is still interleaved, but the SIMM slots are gimped.

I never thought much of the 650 and 800 machines until I started messing with the memory controller. Now, they're pretty much my favorite 040's. Solder on a ROM SIMM slot, put a modified ROM on there to disable the RAM check and enable the 128mb SIMMs, and just have fun with a ~300MB RAM disk.