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  1. #1
    Join Date
    Jul 2008

    openGL renders incredibly slowly on some computers

    I have written a simple program which renders a harmonic oscillator in openGL, and when i run it i get about 30 fps on my "main" computer, which is capable of running games like Crysis faster than 30 fps.

    However, when i run the exact same executable on my laptop (a significantly slower computer) i get framerates which are about a order of magnitude higher (about 300 fps).

    My main computer has a "GeForce 9800 GTX/9800 GTX+/PCI/SSE2" graphics card, which supports openGL 2.1.2 ( according to glGetString(GL_RENDERER) / glGetString(GL_VERSION) ) while my laptop uses a "Intel Cantiga" (some sort of integrated card probably? ) and supports version 1.5.0 Both computers are running windows XP, the slower one is 64-bit;

    I was wondering, does anyone know what this might be caused by? It is quite evidently not the program itself, but rather some sort of library / driver maybe?
    Last edited by Afr0; April 19th, 2009 at 11:08 AM.
    Title: Subject: Read subject of title.

  2. #2
    Join Date
    Oct 2006

    Re: openGL renders incredibly slowly on some computers

    I've heard that some graphic cards are incredibly slow when handling images with a non 2-based size (i.e. 64 * 128 pixels and so on).
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  3. #3
    Join Date
    Jul 2008

    Re: openGL renders incredibly slowly on some computers

    Ah, thank you for you your reply, however, that is not the case. I am actually not drawing any images, but three line strips consisting of about 500 vertices each. Even when not drawing anything at all this problem persists.
    Title: Subject: Read subject of title.

  4. #4
    Lindley is offline Elite Member Power Poster
    Join Date
    Oct 2007
    Seattle, WA

    Re: openGL renders incredibly slowly on some computers

    Odds are you're hitting a software (as opposed to hardware) rendering path for some reason. Couldn't guess why without seeing the code. A good starting point would be to print out the glGetString(GL_EXTENSION) lists from the two machines and compare them to see what's missing on the slower machine.

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