Could someone please lend a hand? fortran issue

[papasmurf]

Hello Folks,

I've been writing software on an athlon 2200xp using absoft fortran to compile my fortran code to executable files.

Today I purchased a shiny new HP zd8181ea with pentium a 3.2Ghz 4 processor (#640). I've heard marvellous things about this processor and spent the lions share of my student grant on the laptop.

I have tried compiling the code on the new machinebut when I execute it it takes around 50 times longer to complete than my old battered desktop.

I have also tried salford fortran 95 personal edition but the final compiled program take just as long to finish. Have I wasted my money on this laptop or have I missed something important when compiling/writing the code?

Thanks for any advice,

Bren

P.S. I know that between different processors there can by a "Kind" difference that can cause problems. I've used the "selected_real_kind" function to choose an appropriate variable kind for all double precision variables. I'm sure that the problem I'm seeing isn't a "kind" issue.

[Steven_L_Intel1]

Unfortunately, desktop processors in a laptop are not likely to give you good performance. The laptops "throttle" the CPU in order to manage the heat generated. Intel does not recommend desktop processors in laptops for this reason, but manufacturers use them because they're cheaper than processors designed for mobile use.

Other issues are disk speed (laptop disks are slower than those for desktops) and RAM limits may also be an issue.

You need to first determine what is responsible for the poor performance - is it CPU speed, or perhaps excessive paging due to inadequate RAM? If you bring up the task manager performance monitor, you want to see the CPU load at 100% while running the program, and, ideally, little disk activity.

Since you have a Pentium 4 640, make sure you compile with the /QxP option (Pentium 4 with SSE3 Extensions) and Maximum Optimization.

You'll also want to give the laptop plenty of ventilation, and be sure it's running on AC power.

[jim_dempsey]

Must be either the optimization settings (be sure to set default real size to real(8) too), or not enough RAM (or too much baggage that came with the laptop).

I have a Toshiba Satellite P35-S6292 with Pentium 4 538 processor (3.2 GHz). This laptop runs my FORTRAN simulation program faster than my desktop system HP Pavilion a730n with Pentium 5 530 processor (3.0 GHz).

My laptop has 1GB RAM and my application takes over 512MB of RAM.

Also, check the individual source modules in your projects to see if they inherited the settings from the project options. WhenI first transported my solution file and project files from the desktop to the laptop many of the source files in the Release configuration ended up with the optimization settings for the Debug configuration. Never found out what the cause was but all is fine now.

Jim