Hi Fabio,

if you know you are handling sizable strings, you could always reach back into the old tricks:

t1=SECONDS()
FOR K=1 TO 10
	 lnX = STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")+ ;
	 	STRTOFILE(m.x, "NUL")
NEXT
? lnX, "StrToFile >> Nul",SECONDS()-t1

t1=SECONDS()
FOR K=1 TO 10
	 lnX =LEN(m.x) + LEN(m.x)+ ;
		LEN(m.x) + LEN(m.x)+ ;
		LEN(m.x) + LEN(m.x)+ ;
		LEN(m.x) + LEN(m.x)
NEXT
? lnX, "Len() summed",SECONDS()-t1

gives on a few of my machines very competitive and suprisingly similar resutls if added into your test program.

regards

thomas