The output for my version first and the default version afterwards is

#<time type: time-duration nanosecond: 449629000 second: 8>dak@lola:/usr/local/tmp/guile$ meta/guile /tmp/zoppo.scm 
#<time type: time-duration nanosecond: 898802000 second: 15>dak@lola:/usr/local/tmp/guile$ 

So it's a bit better than my 7:4 estimate (rather a factor of 1.88),
probably because I forgot that the CPU does not have to wait for the
write cycle to complete for continuing.

Now that's a somewhat artificial benchmark, but still: almost a factor
of 2 for the operation itself is pretty good.

-- 
David Kastrup