I don't know why you guys even bother to calculate FPS.
The game literally does it for you.
Dvar is disabled but reversing isn't hard.
The game calculates the FPS for DrawActiveFrame() which is called 2x per frame ( SterioFrame + Normal ). Divide by 2 to get your actual FPS.
// Yes, these are stored as floats but have no decimal precision. Coerce them.
int m_fps = *(float*)0x58DA4B0 / 2;
int m_fps = MemC.ReadFloat( 0x58DA4B0 ) / 2;
Easy and avoids unnecessary CPU power.
Not that it needs credits but yea, found it myself.