2011 iMac - MDP(via Thunderbolt) to DVI converter causes mouse to skip/jump

Discussion in 'iMac' started by MACza, May 19, 2011.

  1. MACza macrumors member

    May 10, 2011

    OK - I had my 2011 21.5" iMac now for a week. Loving it so far!!

    BUT there is an issue - I am using my 23" Samsung monitor from my retired PC (Good riddance!!! :D) as a secondary display via a MDP to DVI connector (the official white Apple one).

    The funny thing is, when the MDP is plugged into the Tbolt port - it causes my mouse pointer to skip/jump. It is extremely bothersome, especially when trying to do precise graphical/photo work. I have tried all settings, other mice etc. The skipping/jumping happens when the 2ndary display is switched off.

    The skipping/jumping DOES stop as soon as I remove the MDP to DVI connecter from the Tbolt port though - talk about strange!!! :eek:.

    I must still test this when the 2ndary display is OFF - I seem to recall that it was fine when the 2nd display was switched on as well. I will test this more later today to have some properly tested results.

    Anyway - has anybody else experienced this mouse pointer skipping/jumping happening when using the MDN to DVI converter???

    Any pointers or advice will be much appreciated :D
  2. MACza thread starter macrumors member

    May 10, 2011
    Well, I just confirmed my suspicions!

    Case 1:
    Second display switched off, but MDP to DVI connector connected to 2nd display.
    Result 1:
    Mouse skips/jumps every 4 seconds (testing just by moving the mouse cursor in a circle continuously)

    Case 2:
    Second display switched on and connected via MDP to DVI connector to iMac.
    Result 2:
    Mouse is silky smooth, absolutely NO skipping or jumping of the mouse cursor!

    Case 3:

    MDP to DVI connector unplugged from iMac.
    Result 3:
    Mouse is silky smooth, absolutely NO skipping or jumping of the mouse cursor!

    THUS - the MDP to DVI connector causes the jumping/skipping of the mouse cursor when the MDP to DVI connector is connected, but the 2ndary display is not switched on.

    Fortunately this is not as bad as I originally feared - I will mostly work with both displays powered up. It is just that sometimes I would only use the iMac by itself and will then have to unplug the MDP.

    I hope Apple can fix this - where does one formally log an issue with Apple on technical issues?

  3. gcthompson macrumors newbie

    Apr 6, 2010
    That is strange, I have 2 external DVI monitors plugged in and don't experience the same issues. How much VRAM does your video card have?
  4. sth macrumors 6502a

    Aug 9, 2006
    The old world
    Report it to Apple, probably an issue with the Thunderbolt drivers. http://bugreporter.apple.com/
    I'd also post the question in the official support forums since Apple seems to read those as well.
  5. MACza, May 19, 2011
    Last edited: May 20, 2011

    MACza thread starter macrumors member

    May 10, 2011
    Thanks sth - I will do that. It seems this is a problem that has been reported before, will post some links a bit later...

    Here is a link - seems this was previously fixed via a patch, must have slipped back in with Snow Leopard/Thunderbolt introduction:

  6. Bardofar macrumors newbie

    May 6, 2011
    Im also gonna connect a second monitor to my 27" imac, mdp to dvi. Im gonna go to the store tomorrow and get a original Apple connector. Ill let you know if im experincing the same issue with the skipping mouse.
  7. danseq, Jun 4, 2011
    Last edited: Jun 4, 2011

    danseq macrumors newbie

    Jun 4, 2011
    I'm having exactly this problem with a new MacPro 3.33Ghz machine.

    I have three monitors.

    1. 2560x1600 30" samsung 305t on a Gefen extender
    2. a 17" Dell on a USB->DVI displaylink adaptor

    Mouse has been fine up till now with those.

    When I added a 40" Sony 1080p TV (using a 3rd party minidisplay to HDMI adaptor) that's when I started having the mouse skipping problems. It's driving me nuts. When I remove this display and reboot, the problem goes away.

    @Bardofar--did the apple branded MDP to DVI work to solve the problem?



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