Results are in: static foreach is a slower than hand unrolling your loops or using mixins.

[Gareth Charnock]

I managed to get some free time to look at this and it would appear that 
static foreach is slower than hand unrolling a loop. Fortunately there 
are no detectable differences between hand unrolling a loop and building 
the body of the loop in a compile time string and using a mixin. Results 
are here:

http://github.com/gcharnock/phoboslinalgebra/blob/4d1f62ce2f866acf24f237be77a2b59158571de0/staticloop_results.txt
Test program is here:

http://github.com/gcharnock/phoboslinalgebra/blob/4d1f62ce2f866acf24f237be77a2b59158571de0/staticloops.d