very slow runtimes

very slow runtimes

Is anyone else using MS Developer Studio and Intel Fortran 7.0? I've been using CVF 6.6A and I'm testing the waters of transition and finding very large differences in run times. My current example:

-2000 lines of code
-many allocatable arrays
-virtually all the work is floating-point
-runtime with CVF: 171 s
-runtime with IF: 987 s (!)

I've set optimizations to "maximum speed" with no debugging. The options produced by the Intel Fortran compiler build tool are:

/O2 /G7 /4I4 /4Na /Ob2 /4L72 /Quppercase /Qpc80 /4Nb /ML /Qrcd /Qdps /c /w90

I'm running a P4 @ 2 MHz. (I know of the modest floating-point slow-down that can occur with the P4--but surely not a factor of five!)

Any ideas?


1 post / 0 new
For more complete information about compiler optimizations, see our Optimization Notice.