| With the information given we can only guess at the performance
behavior you are seeing.
On all current Alpha systems, the time for add, sub and mul is the
same for single and double precision. Single division is faster than
double division and most math library routines are faster for single.
However, the speed of computation is probably not responsible for the
performance differences you are seeing. Double precision data is
twice as large as single precision data so a program calculating with
double precision data often needs double the memory bandwidth. The SGI
Origin series has very good memory bandwidth so increasing the data set
size should improve the SGI performance relative to Alpha.
Future Alpha chips will have a big improvement in potential memory
bandwidth over existing chips.
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