🚀 go-pugleaf

+-------
| You may be running software that has a very low cache hit rate if you
| are doing CAD work or scientific calculations.  Take this little loop
| for example:
| 
|    SUM = 0.0
|    DO 10 I = 1, 1000000
|      SUM = SUM + VEC(I)
| 10 CONTINUE
| 
| A data cache is *no use at all* for this problem.  You will get a
| cache miss on every data access.  Similarly, copying data from one bit
| of memory to another will be limited by the raw memory speed.
+-------
Unless your d-cache line size is wider than a word, and performs burst refills
from main memory.  The '486, for example, will burst fill the 4-word line if
suitably equipped with nibble-mode DRAMs.  Assuming two wait-states for the
initial access, and zero wait states for the sebsequent three, the result is
0.5 wait-states for your example.  Granted, you're still busting the d-cache,
but you are able to take advantage of nibble-mode DRAMs (which tend to be
about the same price as regualr DRAMs).

Bruce "and why would anyone be running FORTRAN code on a PC :-)" Kleinman