I’ve just done a quick and nasty comparison of runtimes using GNU Fortran and the recommended compiler flags from here. I used a CFD code mentioned earlier.

Compiling as before (`gfortran euler.f`

) gave a runtime (using `time`

) of:

`CALCULATION CONVERGED IN 3490 ITERATIONS

TO A CONVERGENCE LIMIT OF 4.99999987E-06

**real 1m6.156suser 1m4.030ssys 0m0.300s**`

Next, I compiled using `gfortran <strong>-march=armv6 -mfpu=vfp -mfloat-abi=hard</strong> euler.f`

with the following result:

`CALCULATION CONVERGED IN 3490 ITERATIONS

TO A CONVERGENCE LIMIT OF 4.99999987E-06

**real 1m5.127suser 1m3.800ssys 0m0.330s**`

So a slight speed increase is shown. This difference would probably be amplified when more complex code is compiled. I had none to hand, alas.