これだとfloatの方が遅くなるのはなんで？

#include <windows.h>
#pragma comment (lib, "winmm.lib")
#include <mmsystem.h>
#include <stdio.h>

int main ( void )
{
#define FL
#ifdef FL
float n = 1 ;
#else
double n = 1 ;
#endif
timeBeginPeriod(1) ;
unsigned long start_time = timeGetTime() ; // 計測開始時間
#ifdef FL
for ( float i = 1.0f ; i < 10000000.0f ; i+=1.0f ){
#else
for ( double i = 1.0 ; i < 10000000.0 ; i+=1.0 ){
#endif
n += i ;n -= i ;n *= i ;n /= i ;
}

unsigned long end_time = timeGetTime() ;
timeEndPeriod(1) ;
printf( "%d\t", end_time - start_time ) ;
return 0 ;
}