var
// f,f1:single;
f,f1:double;
i,c:integer;
begin
c:= GetTickCount ;
for i := 0 to 1000000 do
//if f=f1 then Continue;
f:=f+f1;
Caption := inttostr(GetTickCount -c);


执行 f=f1 时:

single用时740
double用时500


执行f:=f+f1时:
single用时400
double用时500