Compaq Visual Fortran v.6.0.a - Windows 2000 - PIII1.9GHz

[efthimios]

Can anybody advice me what should I do in order to optimize my system to ran faster a code written in Compaq Visual Fortran 6.0.a in a Pentium 4 1.9 GHz - Windows 2000 computer. Comparing this system against a P4-1.6, under Windows XP I have found that the second is getting better although it has lower CPU capacity and Memory (256 MB against 512MB of mine). Thank you very much.

[Steven_L_Intel1]

Put Windows XP on the 1.9 system? There can be many variables that affect performance, there's no universal solution.

I'll also note that DVF 6.0 (it wasn't Compaq then) is four years old - the compiler has improved a lot since then and can speed things up on a Pentium 4. Invest in the upgrade to 6.6 - if speed matters to you, it should be worth it.

Steve

[rshepherd]

This may be too late but I'd be careful before committing to a higher compiler version.

We have used Visual Fortran 6.0 happily for several years.
Finally one of the optimizer bugs with registers not being managed correctly forced us to upgrade to 6.1a.

This solved the bug but we were horrified to find that the speed of some of our standard test runs were 2 to 3 times slower even with all the optimizer tweaking possible. (e.g. going from 103s to 282s)

Since then we have evaluated 6.6a and its better (same example - 236s) but still not as good.
These results are on the same hardware (p4 2ghz), same operating system (win2000), same code - just the compiler settings experimented with and optimized in each case.
As stable is better than performance for our product we have had to follow this upgrade path.

I suggest you ensure you still have your 6.0 disks to hand before you overwrite with a higher version.

(Alternatively, if anyone thinks I've missed something stupid when upgrading, I'd be very grateful if you'd let me in on it!)

[Steven_L_Intel1]

This is very unusual - I don't recall seeing any reports of such behavior. To the contrary, most of our customers find that run-time performance is significantly better in the newer versions.

If you have a test case we could look at, please send it to vf-support@compaq.com (we'll need a ZIP archive of the project sources and instructions for building and running the program.)

Steve