Hi Pepe
You cannot say which is faster, the LV or the C programm. The only way to be sure is to program in both environments and to check than. Check this for some benchmark examples:
http://zone.ni.com/devzone/conceptd.nsf/webmain/DC9B6DD177D91D6286256C9400733D7F?OpenDocument&node=200059
Luca
Regards,
Luca