There were many kinds of SIMMs for GVP boards, not all of them is special:
8 bit, 30 pin - used on their Impact SCSI controllers (A500 HD8, A2000 HC+8). Nothing special.
8 bit, 30 pin, Nibble mode - used on their A3001 accelerator. Special, but not a GVP speciality, as it was used in Suns too.
32 bit, 64 pin - used on most of their older accelerators. Special GVP made stuff, available in 1, 4 or 16 MB form.
32 bit, 68 pin - used only on the G-Force 040/3000. Special non-multiplexed, 1MB, 40 ns SIMMs.
32 bit, 72 pin - standard SIMM, used on their newer accelerators (GVP-M).
