mnesia memory usage on 32 and 64 bits machines

[franz]

Hello everybody.
I would like to know your opinions about a load test I'm doing, whose 
result quite shocked me.
Briefly, I created a mnesia ets table and inserted 50000 records into it.
I tried this bulk load on two machines: the first, say it A, running a 
64bits kernel on a 64 bits machine, the second, say it B, running a 
32bits kernel on a 64 bits machine.
On A the records occupy 202707450 words of mem, and misuring the RAM 
consumption before and after the insertion I know that they occupy 1560Mb.
On B the records occupy 202707473 words of mem, with a RAM consumption 
of 795Mb.
On one hand this makes sense, because as far as I know a word of mem on 
a 32bits machine is 4 bytes, 8 on a 64bits machine. But does this mean 
that having a 64 bits kernel doubles the memory usage?!?
Thank you all and happy new year,
franz