Sapphire Radeon HD for Mac in MP5,1

Discussion in 'Mac Pro' started by bxs, Jun 18, 2014.

  1. bxs, Jun 18, 2014
    Last edited: Jun 18, 2014

    bxs macrumors 6502

    Oct 20, 2007
    Just installed this card in slot 1 in my MP5,1. It's brand new one. I made sure the firmware switch on the card was to the right for the Mac OS X. Both power cables that came with the card were employed.

    I connected a 23" ACD via DVI to MDP and attach to the left most MDP (furthest away from the HDMI port). When I Startup the screen lights up and at about the time the login panel is about to display the screen goes black.

    If I disconnect the ACD from the MDP when the screen has gone black and then reconnect it to the same port the screen lights up and the login display appears.

    If I connect to the other MDP the issue does not arise.

    If I connect directly to the DVI the issue does not arise.

    Any clues why the screen should go black as I've described ?

  2. h9826790 macrumors 604


    Apr 3, 2014
    Hong Kong
    Will that happen if you boot into recovery partition? Or run the Apple Hardware Test?
  3. omvs macrumors 6502

    May 15, 2011
    Is the login screen using filevault or not? If not, that would be about the time the video drivers kick in -- and I'm curious what other versions of OSX would do.

    Another thing to try might be to set the dip switch to PC mode - you'll lose the EFI bootscreen, but if you're not using file vault you likely don't need it. I had to do that to workaround a issue with a 4k display, and once OSX booted card worked fine.
  4. bxs thread starter macrumors 6502

    Oct 20, 2007
    The card exhibits same issue running Yosemite 10.10 build 14A261i.

    No file vault being used.

    Placing the dual firmware dip switch to left for "UEFI for Windows PC" mode does in fact resolve the issue for both 10.9.3 and 10.10. It also causes no issue when booting to the Recovery partition under 10.9.3 and Yosemite 10.10. The login panel is always displayed correctly in all situations.

    Will having the switch in Windows position interfere with the cards performance under Mac OS X ?


    I ran Cinebench R15 with switch in 'Windows' position and the FPS value was almost identical to what I got using the card with switch in 'Mac OS X' position.

    Just what is the difference in running the card with the switch in 'Mac OS X' vs. 'Windows' when employing Mac OS X 10.9.3+ ?
  5. omvs macrumors 6502

    May 15, 2011

    I didn't notice any in OSX, though any had it there for a few days (and I no longer have the card to test). If there was a major difference I believe I would have seen it -- but a subtle difference like the PCI link speed going to 1.0 could occur and I wouldn't have noticed.

    My understanding is the PC switch is *only* really intended if you're going to put the card in a PC, otherwise the PC wouldn't get a bootscreen. Normally you'd want the EFI position just for the boot, but once OSX or windows drivers load they take over and it doesn't matter, so as a workaround it might be fine...
  6. bxs thread starter macrumors 6502

    Oct 20, 2007
    I have an Apple 27" and 30" display, so will connect these to see if the issue is related to just the 23" ACD.

    Thanks... for you responses. :)
  7. omvs macrumors 6502

    May 15, 2011
    Don't forget you have to use an active mDP->dual link DVI adapter for the 27/30". I'm guessing you're using one of the passive single link adapters for your 23", so just the adapter change may make the card act differently.
  8. bxs thread starter macrumors 6502

    Oct 20, 2007
    I just restarted the MP5,1 with the 23" connected to the left most troublesome Mini Display Port and then used my MBP8,3 to share the MP5,1's screen and the shared screen on my MBP8,3 clearly showed the login panel while the 23" remained black. I used the shared screen on my MBP8,3 to login and that went without issues, yet the 23" on the MP5,1 continued to display black. This was all done with the Dual Firmware switch on the 7950 set to the Mac position.

    I'm guessing at this time the issue is related to to 23" and maybe its DVI to MDP adapter I'm using as you've implied. Thanks.... :)

    I have another MP5,1 with the 7950 and will later today connect this 23" display to it using the left most MDP. If the issue is the same I will assume the 7950 is operating correctly and that the issue is related to just the 23" and its DVI to MDP adapter.
  9. drewsof07 macrumors 68000


    Oct 30, 2006
    I had issues with all mini display ports under 10.9.2 on my XFX 7870, worked fine under 10.9.1 then were resolved with 10.9.3. Maybe a lingering issue resolved for PC cards but still impacting OS X ROM? Haven't been brave enough to boot into 10.10 yet. Challenge accepted :cool: ... but maybe over target disk first :eek:
  10. bxs thread starter macrumors 6502

    Oct 20, 2007
    I returned the troublesome 7950 to OWC and they were kind enough to send me a replacement within 2 days. The replacement 7950 does not have the same issue as described in my OP. Thus, the 7950 I originally received had a faulty MDP seemingly.

    All is good now. :) Thanks for all the replies.

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