Intel ARCHITECTURE IA-32 - Manual (Page 557)

Mathematics of Prefetch Scheduling Distance
E
E-11
memory to you cannot do much about it. Typically, data copy from one
space to another space, for example, graphics driver moving data from
writeback memory to write-combining memory, belongs to this
category, where performance advantage from prefetch instructions will
be marginal.
Example
As an example of the previous cases consider the following conditions
for computation latency and the memory throughput latencies. Assume
T
l
= 18 and T
b
= 8 (in front side bus cycles).