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msanna

macrumors newbie
Original poster
Aug 17, 2015
1
0
Hi guys,

Was hoping to get some insight from everyone regarding whether or not I can upgrade my GPU in my Mac Workstation tower (the grey one) from its original AMD card (not sure of the exact model) to an Nvidia GTX 980 Ti.

So far, having done a bit of research, from what I understand, this can be done, but as a result I will have some inability to see my boot screen? Is this something that is easily fixable, or else how do I work around this?

Also, the GTX 980 and cards similar to it require both a 6 pin AND 8 pin PCI-E power connector in order to run. Is there any risk of causing damage to my Mac if I plug in a 6 AND 8 pin, seeing as originally there was only a single 6 pin? I hear that Mac 6 pin connectors are only rated for 75W and that the 8 pin will take 150W, is this dangerous to do because of this fact?

Thanks in advance for any help regarding this, I really am struggling to find a clear answer.

-Mark
 
I am not a Nvidia boy now (may be later when Apple provide some native support to the 9xx serious card).

Anyway, AFAIK...

Yes, you can upgrade your AMD card (whatever it is) to the 980 Ti.

For a normal PC version 980 Ti, you won't have the boot screen. And the fix is easy, pay someone to do it properly for you (unless you know how to write the EFI by yourself).

If your computer works fine, most of time you don't need the boot screen. However, it may be a bit messy if something went wrong and you want to see what's happening during boot / access the recovery partition. The cheapest work around is to keep your AMD card, and install it back into the Mac when you need it.

And yes, there is always a risk if you allow the card to draw more than the mobo can provide. However, when I play around with my 7950, I OC it to draw >100W from a single 6pin supply. No issue so far. Of course, it's just a "for info" for you, and doesn't mean that your Mac will work exactly in the same way. You may cook your mobo by overloading it and it cost you few hundreds to fix it.

If money is not a big issue to you. Then you better get a 980Ti from MVC, he already wrote the EFI for this card, and he can mod it to become a 2x6pin card. Which remove all your doubt.

However, I must remind you that hardware limitation is not the only issue. You can study the thread about PSU mod, or install and extra PSU to solve that. Or most likely you can just use a 6pin to 8 pin adaptor to run the card without any issue. Besides that, you also need to know the minimum OSX version required and also how to install and activate the Nvidia web driver.

Without proper OSX version and driver, the card will only give you black screen but nothing else.
 
Probably easiest solution in your case is to buy a stock 980 Ti and send it to MVC for flashing service. Use a 6-to-8 pin adapter. It can safely run on internal power only and you'll have boot screens. If you're really worried about power you can use Nvidia Inspector to throttle the power consumption limit to 225W.
 
The biggest issue that people have trouble with is that these cards require Yosemite AND Nvidia Web Driver. We have this listed all over out website but still get pretty regular "Why won't this boot into Mt. Lion?" questions after the fact.

There is no "fix" to get this into 10.9.5 for instance. The EFI gets you some ease with OS updates but they still aren't as easy as they would be if Apple got off their butts and added the drivers into the core OS.

You can see test results of speed at Barefeats.com
 
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