Mac Pro 3,1 - Bad GPU choice?

Discussion in 'Mac Pro' started by lewis_cooper, May 15, 2016.

  1. lewis_cooper macrumors newbie

    lewis_cooper

    Joined:
    May 9, 2016
    Location:
    London, UK
    #1
    Hi everyone,

    I have a Mac Pro 3,1 (2008) 2.8ghz running El Capitan and have decided I want to get into video editing using either Final Cut Pro X or Adobe Premiere Pro (a decision yet to be made) and a bit of GoPro Studio.

    I currently have the ATI Radeon HD 5770 1024 MB installed and video playback / scrubbing is very choppy so wanted to upgrade my GPU.

    I understood that there are a great many PC cards that can be used so long as I'm prepared to forego the boot screen or flash the EFI. So I decided to go the PC card route and ultimately opted for the following card:

    Gigabyte GeForce GTX 960 OC 4GB GDDR5 Dual Link DVI HDMI DisplayPort PCI-E Graphics Card (links through to exact model purchased and price paid).

    I settled on this card, reassured that it was being offered by macvidcards.

    However, what I can't get my head around is how much should I worry about the fact that it's the GTX edition with "OC" (presumably overclocked?). Does that mean it'll draw more power than a non OC version and therefore cause stability issues?

    Also, macvidcards mentions OpenGL and OpenCL support on their page but I can only find mention of OpenGL on the Ebuyer page. I figured some degree of OpenCL would be essential in case I decided to learn/use FCPX.

    So, in summary:
    - at £170 have I bought the best card for my buck / pound
    - if not, what should I buy instead for the same budget or less
    - will it cause me issues with power draw (bear in mind it's 4GB)
    Would love to hear your thoughts before the I crack open the packaging!

    Cheers,
     
  2. Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #2
    The GTX 960 draws 120 Watt. Mac Pro provides 225 Watt. So no problem when a OC'ed versions draws a little bit more.

    http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-960/specifications
     
  3. lewis_cooper thread starter macrumors newbie

    lewis_cooper

    Joined:
    May 9, 2016
    Location:
    London, UK
    #3
    Thanks Synchro3. The link you provided is for a 2GB version of the same card though. Will it be different for the 4GB version that I ordered. On its manufacturer's page it says recommended PSU of 400w which seems much higher than 225 watt. Or am I misunderstanding this aspect?

    Thanks again.
     
  4. Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #4
    On the manufacturer's page is not written how much the card draws under stress (TDP).

    Has the card a 6 pin and 8 pin power connector?
     
  5. lewis_cooper thread starter macrumors newbie

    lewis_cooper

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    #5
    I've found this info of the card:

    System PSU Limitation 400
    GPU (TDP) - 136(Real)
    Total Graphics Power (TGP) - 180(Real)

    Yes I believe so. And if not in the box it has the slots:

    [​IMG]
     
  6. Synchro3, May 15, 2016
    Last edited: May 15, 2016

    Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #6
    Ok, the 8 pin connector can draw 150 Watt, the 6 pin 75 Watt, too much for Mac Pro (2 * 6 pin).

    Use an external PSU, do a mod with the internal PSU, or a workaround with adapters (2 * 6 pin to 8 pin adapter and 2 * SATA to 6 pin adapter).

    However, I don't think a GTX 960 is worth for extensive work. You can have a GTX 980 which fits in the power envelope of Mac Pro with 2 * 6 pin connectors.
     
  7. h9826790, May 15, 2016
    Last edited: May 15, 2016

    h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #7
    Recommend 400W PSU because the computer has CPU, HDD, mobo, etc., not just the GPU. In fact, a CPU can easily consume 100W. Also, AFAIK, the 400W may means the max output is 400W, not minimum, under high temperature etc, the output may be lower than the rated number. Therefore, GPU manufacture will recommend a PSU that has much higher power rated then the GPU itself.

    These are all directly from Nvidia. As you can see. They recommend a 400W PSU for the 120W 960. For 980Ti (250W), they will recommend a PSU rated 600W or above.

    Screen Shot 2016-05-16 at 06.55.26.jpg Screen Shot 2016-05-16 at 06.55.47.jpg Screen Shot 2016-05-16 at 06.57.20.jpg
     
  8. lewis_cooper thread starter macrumors newbie

    lewis_cooper

    Joined:
    May 9, 2016
    Location:
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    #8

    Thanks Synchro3 and h9826790. I really don't want this to get messy with anything like an external PSU, especially not for my needs, so I will look for an alternative GPU.

    Just to re-iterate my needs I currently have the ATI Radeon HD 5770 1024 MB installed and video playback / scrubbing is very choppy.

    I want to be in a situation where editing is as smooth as possible on my setup without any delays or stutters whilst scrubbing and during playback.

    Does anyone have any suggestions?
     
  9. Fuchal macrumors 68020

    Joined:
    Sep 30, 2003
    #9
  10. lewis_cooper thread starter macrumors newbie

    lewis_cooper

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    #10
  11. ActionableMango macrumors 604

    ActionableMango

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    Sep 21, 2010
    #11
    Your 960 is fine. The reference model is 2x 6-pin and that tiny factory overclock will not add an appreciable amount of wattage. The 960, even overclocked, uses significantly less wattage than the cards people are recommending with 2x 6-pin connectors. The two extra pins on that 8-pin connector are almost certainly cosmetic marketing BS for the overclocker crowd, as we've seen on many other cards, and are not actually required as it is on other cards like the 980Ti.

    Get two normal 6-pin Mac Pro GPU cables and connect them to the 6-pin and 8-pin connectors on the card. The 8-pin connector on the card is keyed to accept the 6-pin cable.

    AFAIK, all modern cards in the last several years support OpenGL and OpenCL. I would not worry about that omission.
     
  12. lewis_cooper thread starter macrumors newbie

    lewis_cooper

    Joined:
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    Location:
    London, UK
    #12
    Hi ActionableMango,

    Thank you very much for your considered response. This is a turn of events!

    So… you are advising me to keep this card and you don't expect me to have any problems? How confident are you about this?

    Sorry to doubt you, it's just that it contradicts the advice I've been given so far. I do hope you're the one who is right though! :)

    So by only using 6-pin cables even on the 8-pin connector on the card am I somehow limiting the power draw? Is that why you are not recommending to buy an 8-pin to 6-pin cable like this?

    One last question, do you think I should've chosen a different card altogether? One that I can flash maybe so I'm not limited to PCIe 1,1 speed?

    Cheers!
     
  13. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #13
    The people giving you the contradictory advice are smart people and I respect their knowledge and general willingness to help. However, this is an edge condition that I don't think they have personal experience with.

    As I said before, the 8-pin connector is keyed to accept either 6-pin or 8-pin power, so it's up to the card whether it really needs the extra power or not. Some cards like the GTX980Ti really do need that extra power. Some like my GTX680 FTW do not.

    The two extra pins on the 8-pin connector are ground and sense, not extra power like you might guess. The sense pin lets the card know whether a 6-pin (75W) or 8-pin (150W) cable is connected to the 8-pin socket.

    I personally did this with my GTX 680 FTW (an overclocked model) that had 1x6-pin and 1x8-pin. (The GTX680 reference model, like the GTX960 reference model, is also 2x6-pin, so this is exactly the same scenario for you.)

    For your card, I'm reasonably confident it will be fine for three reasons: (1) The reference model GTX960 is 2x6-pin, (2) my GTX 680 uses a whopping 63% more wattage than your GTX 960 so I think you'd be WAY WAY WAY fine, and (3) even with the strongest load I could put on it (Furmark), hwmonitor showed that I never exceeded a 75 watt draw on each of the three power sources (two 6-pin cables and PCIe slot).

    All that being said, I cannot guarantee anything because I haven't used that exact card. If you are still worried about it, use hwmonitor to monitor your power draw. I suspect you will see the same thing I did... no GPU power source exceeding 75 watts.

    Sorry, I do not have the experience to know what specific card to recommend for your purposes. Other people will have a better idea.

    But I will say that, regardless of the card model, I personally wouldn't run a computer without boot screens. I'd either want to flash my card (as I did with my GTX680), pay for a flash from MVC (as with my 980), or keep an older spare card with Mac EFI. There are many, many reasons to have boot screens, especially so with a Maxwell card like your GTX 960. I hope you fully understand the OS X driver update routine for Maxwell cards, and the problem with accidentally screwing that up if you have no boot screens (which is all avoided if you have a Mac EFI).
     
  14. lewis_cooper, May 21, 2016
    Last edited: May 21, 2016

    lewis_cooper thread starter macrumors newbie

    lewis_cooper

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    #14

    Okay, so good news. The card is in, the system recognises it and I've had no apparent problems whatsoever. The card had 2*6-pin ports as per the reference model, so I bought the recommend Mac Pro-specific cables (though only needed 1 as my previously installed 5770 was using one). So thank you for encouraging me to just give it a go.

    I have to say, it's marked improvement over my previous card, but I still feel somewhat underwhelmed.

    What tests can I run to compare against other GPUs? I can't help but feel as though I might be better of trading this 4GB card for a 2GB card that I can flash for 100% mac comparability.

    Any thoughts?
     
  15. benjaprud, May 21, 2016
    Last edited: May 21, 2016

    benjaprud macrumors member

    Joined:
    Apr 9, 2015
    #15
    It's hard to reliably test the general speed of a graphics card on OSX because drivers and most software have limited support and poor optimization for some GPUs. The results may not vary accordingly to the actual potential of the card, and may also vary depending on the software used. The best test is your general feeling while doing your day to day tasks, because in the end it's what it's all about.

    If you use it for gaming then the best and cheapest upgrade you can offer yourself is to install a BootCamp partition, otherwise you may be underwhelmed by the performance even of the best graphics card. The 960 4GB is a good card and should be enough for fluid 1080p gaming. If you use it for pro apps then... well... I don't know much about it. Flashing the card will bring the boot screen but won't improve performance, using Windows will.

    It may help if you told us what you intend to do with your graphics card and what are your expectations.

    [EDIT] Oops, just read the OP again. If you use pro apps then... well... I'm out.
     
  16. lewis_cooper thread starter macrumors newbie

    lewis_cooper

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    London, UK
    #16
    Haha. Good job you re-read it before I had a chance to reply. ;-)

    No, I'm not a gamer so the performance I care about is video editing performance.
     

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