Does using an external monitor on my iBook effect framerate?

Discussion in 'Games' started by bnemesis, Aug 10, 2004.

  1. bnemesis macrumors regular

    Joined:
    Jul 31, 2003
    #1
    Say, for example, if I am playing UT2004, and I want to use an external 17" monitor. Will doing that make the game run worse than if I just used the lcd?
     
  2. Nermal Moderator

    Nermal

    Staff Member

    Joined:
    Dec 7, 2002
    Location:
    New Zealand
    #2
    If I had to guess, I'd say no, because the video chipset is doing the same amount of work regardless of how many displays are connected. I believe that since the iBook uses an analogue output, this output is split between the LCD and VGA port, and as far as I know there is no processing required for splitting a signal.

    That was quite possibly the most difficult-to-follow answer I have ever posted on this forum :eek:
     
  3. Adurbe macrumors member

    Joined:
    Jan 22, 2003
    Location:
    Wales
    #3
    Yes it does

    When you connect an extra moniter vram is split evenly between the two

    ie your running UT with 16 meg of vram not 32
     
  4. ebow macrumors 6502a

    ebow

    Joined:
    Apr 30, 2001
    Location:
    Trapped in a world before later on
    #4
    But it sounds like bnemesis just wants to mirror his laptop's display onto an external monitor. Why would the video RAM need to be split where there's only one image, one array of pixels, being generated? I'm not guaranteeing that performance will be the same, but to me it makes more sense that it would, rather than be halved (or whatever the effect of having 1/2 the video RAM would be).
     
  5. Adurbe macrumors member

    Joined:
    Jan 22, 2003
    Location:
    Wales
    #5
    My iBook via system profiler notice the vram on each display
    (obviously only mirroring as its an iBook)

    ATY,RageM7:

    Type: display
    Bus: AGP
    Display Type: CRT
    Slot: ATI
    VRAM (Total): 32 MB
    Vendor: ATI (0x1002)
    Device ID: 0x4c57
    Revision ID: 0x0000
    ROM Revision: 113-XXXXX-210

    Display:

    Type: display
    Display Type: LCD
    VRAM (In Use): 16 MB
    Resolution: 1024 x 768
    Depth: 32-bit Color
    Mirror Status: Hardware Mirror
    Mirror: On
    Online: Yes

    Display:

    Type: display
    Display Type: CRT
    VRAM (In Use): 16 MB
    Resolution: 1024 x 768 @ 85 Hz
    Depth: 32-bit Color
    Main Display: Yes
    Mirror Status: Master Mirror
    Online: Yes
    Mirror: On
     
  6. Adurbe macrumors member

    Joined:
    Jan 22, 2003
    Location:
    Wales
    #6
    just to be clear you do not half the framerates but halfing the vram, you will lose a few fps (the higher your graphics setting the more you lose)
     
  7. Sol macrumors 68000

    Sol

    Joined:
    Jan 14, 2003
    Location:
    Australia
    #7
    I also use an LCD display and a CRT monitor. Screen spanning and mirroring have no effect on the graphics performance. I even unplugged the CRT to test this. The games I loaded had the same frame-rates with single or dual displays.

    My graphics card is an nVidia Twinview with 32 MB.

    I would recommend running games off the iBook with the LCD display off and the CRT on the lowest resolution/highest refresh rate. Good 3D is about fluidity of motion as well as details.
     
  8. bnemesis thread starter macrumors regular

    Joined:
    Jul 31, 2003
  9. neoelectronaut macrumors 68020

    neoelectronaut

    Joined:
    Dec 3, 2003
    Location:
    Southeastern Louisiana
    #9
    Ah, good info guys. I was heading out today to pick up a VGA converter thingy for my eMac so I could have an extended desktop.
     

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