Could you please provide the full bustest output as requested before?
Bustest depends strongly on the CPU card being used. 030 cards are usually faster on Zorro III, as no mapping logic is needed, 040 and 060 cards are ways slower.
ZorRAM compares to the DKB3128, the limit for both read and write accesses is somewhere around 13.5MB/s - measured with DENEB operating as DMA master from/to ZorRAM (DENEB DMA state machine is fast, the limit is here mainly the rising edge of /DTACK, which is awfully slow due to the pullup structure of that signal, increasing the waiting phase between two DMA accesses).
On 030 systems you will end up with PIO rates of 12MB/s write and 9MB/s read, while 060 based systems (which usually have 128MB of really fast on-CPU-card memory) values of 10MB/s write and 7MB/s read can be expected. Your mileage may vary.
Michael