Turned off VSync but still getting 60FPS in my DirectX 9 application

Question

I have an DirectX9 application which only renders a triangle on the screen, but I am getting a frame rate of 60 FPS no matter if I've got VSync on or not. Why is this?

Here is the code I've done to calculate the FPS, but I dont know if this is the problem to it.

GameTimer.h

#pragma once

#include "Windows.h"

class GameTimer {
public:
    GameTimer();
    ~GameTimer(){}

    void Update();

    float GetFrameTime();

    inline float GetFramePerSec(){return framesPerSec;}
    inline float GetMillSecPerFrame(){return millSecPerFrame;}

private:
    float secsPerCount;
    _int64 prevTimeStamp;

    float framesPerSec;
    float millSecPerFrame;
};

GameTimer.cpp

#include "GameTimer.h"

GameTimer::GameTimer()  {

    _int64 countsPerSec = 0;
    QueryPerformanceFrequency((LARGE_INTEGER*)&countsPerSec);
    secsPerCount = 1.0f / (float)countsPerSec;

    prevTimeStamp = 0;
    QueryPerformanceCounter((LARGE_INTEGER*)&prevTimeStamp);

    framesPerSec = 0.0f;
    millSecPerFrame = 0.0f;
}

void GameTimer::Update()
{
    static float numFrames = 0.0f;
    static float timeElapsed = 0.0f;

    numFrames += 1.0f;
    timeElapsed += GetFrameTime();

    if(timeElapsed >= 1.0f)
    {
        framesPerSec = numFrames;
        millSecPerFrame = 1000.0f / numFrames;

        numFrames = 0;
        timeElapsed = 0;
    }
}

float GameTimer::GetFrameTime() {
    _int64 currentTimeStamp = 0;
    QueryPerformanceCounter((LARGE_INTEGER*)&currentTimeStamp);
    float timeDiff = (currentTimeStamp - prevTimeStamp) * secsPerCount;
    prevTimeStamp = currentTimeStamp;

    return timeDiff;
}

Knowing that it's only a triangle on the screen (no complicated stuff being drawn), it should render over 1000 frames per second if I have VSync off shouldn't it?

default · Accepted Answer · 2015-05-18T13:15:14.753

2

In the CreateDevice call, set the PresentationInterval of the D3DPRESENT_PARAMETERS parameter to D3DPRESENT_INTERVAL_IMMEDIATE.

edited May 18 '15 at 13:15

answered Jun 13 '13 at 20:39

default

2,637
21
44

score 0 · Answer 2 · answered May 31 '13 at 11:26

0

If you're under Windows, is the framerate still limited if you change your theme to Windows 7 Basic? (turn off desktop composition) I think the DWM enforces VSync in a lot of scenarios, some older software that forces a buffer flip often takes ages to redraw its window content.

answered May 31 '13 at 11:26

jameswilddev

582
7
16

Thanks for the reply. I don't know how you turn off desktop composition, but I changed it to Windows 7 Basic, and the problem still occurs - still getting around 60FPS – Danny May 31 '13 at 11:31
Some drivers offer the ability to force VSync. Is there anything in your nVidia Control Panel/AMD/ATi/Intel equivalent? – jameswilddev May 31 '13 at 11:48
I am using a nVidia Graphics card and I did use the Control Panel to turn off VSync – Danny May 31 '13 at 12:16
In this case I consider it likely that the vsync is not being disabled properly. How are you doing this? – jameswilddev May 31 '13 at 12:21
NVIDIA Control Panel > Manage 3D Settings > Global Settings > Vertical Sync (off) – Danny May 31 '13 at 12:33
I meant in your application; the code that says to DirectX "I want VSync off". I believe the nVidia Control Panel only affects OpenGL looking at it. – jameswilddev May 31 '13 at 12:35
ahhh ok. I didn't know about that - So I didnt do it lol. So how do I do this? How do I tell DirectX to turn VSync off? – Danny May 31 '13 at 12:38
http://msdn.microsoft.com/en-gb/library/windows/desktop/bb174349%28v=vs.85%29.aspx Try this. – jameswilddev May 31 '13 at 12:42

score -2 · Answer 3 · answered Apr 25 '17 at 16:13

-2

You got the limit of the monitor it self, which means that the GPU maybe can executes in 1000FPS but the monitor show it on 60FPS

answered Apr 25 '17 at 16:13

Hido

49
13

Turned off VSync but still getting 60FPS in my DirectX 9 application

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