Why does the resolution change during boot up?

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Why does the resolution change during boot up?

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Our Precision R5400 workstation goes through following resolution change during boot up:

640x480@60Hz --> 640x400@70Hz --> 640x480@60Hz --> windows user resolution

During the few seconds that it is set to 640x400@70 (blank screen), it breaks our display signal transmitter which does not recover back to VGA.

Why does the rez change to 640x400@70 in the first place? Is it related to Boot device menu? I know the diagnostics also run at this resolution. Is there a way to avoid this step of resolution change? I'm not using dual boot, and the system is set to boot only from the internal SATA drive and all the other devices are disabled. Any advice will be greatly appreciated.

Thanks,

JC

All Replies
  • jamnh,

    Thank you for using the Dell Community Forum.

    Did you install your video card drivers into the system? If not, you will need to do this in order to get a higher resolution.

    #iwork4Dell

  • Hi Jesse,

    The video card driver is properly installed. But I'm talking about the boot up process before the graphics kick in. 

    1. The resolution is 640x480@60 at the Dell splash screen with F2 and F12 options to go into BIOS and Boot menu.

    2. Then it switches to 640x400@70Hz for 2 seconds with blank (black) screen with _ cursor blinking at the upper left corner of the screen.

    3. Then Windows starts loading at 640x480@60 

    4. Windows starts up at user resolution (in this case 1600x1200@ 60Hz)

     

    My question is why does it go through the 2nd step, and is there a way to skip that?

    Thanks,

    JC

  • So far as I know, there is no way to skip this.  The resolution of 640X480 is standard VGA.  Before all the computers began using the high resolutions to which we have become accustomed, these high res screens were usually referred to as "super" or "extended" VGA.  These resolutions can only be achieved using the Windows display drivers which are not loaded until Windows actually starts.  The boot-up screens, as well as the screen for Windows safe mode are all 640X480 screens.  That is because the standard VGA driver is the only driver that all display adapters have in common.

    Dell Forum member since 2005

  • Thanks for the input.  But I do not have any problem with standard VGA 640x480@60Hz. It's the 640x400@70Hz sequence that seems to be Dell specific perhaps reserved for their own diagnostics and/or boot device menu. In most cases, people do not notice this momentary resolution switch as the screen stays blank. It just appears the boot up screens stay at 640x480@60, but, in reality, it switches to this non-standard mode that affects display signal hardware. 

    Dell does not have an alternate version of BIOS that stays at standard VGA during boot up. 

  • That is great detective work; I would never have noticed.  The period of time you are describing is the time the BIOS code is busy loading the code from the boot device in preparation for the first hand-off.  Since all of that is under the BIOS control, and naturally there is no way to adjust the BIOS screen resolution, I'm afraid you're stuck.

    Dell Forum member since 2005