3 displays on Mac Pro 6,1 D300

[justinhill]

As usual, I didn't read up before trying this. I have two DVI displays connected via mini-dp to dvi adapters and I tried to add a third display to the HDMI port.

It doesn't work. Only two (any two) of the three will work at a time and the Apple website says to use more than two displays I need 'active' adapters.

Can anybody with a similar setup advise me? Do I need to buy the (expensive) Apple Dual-Link DVI adapter? And if so do I need to just buy one of these or do I need to get two (one for each of the DVI screens)?

It's ironic that my 'old' Macbook Pro mid-2015 was able to run two external displays as well as the built-in display - i.e. three displays - but my new fancy Mac Pro can't...

[Southsidemusic]

Your MBP is newer than your ”fancy new MP” just a FYI and we have the same Mac Pro’s and they aren’t new anymore. 6 years and counting

[justinhill]

Originally Posted by Southsidemusic

Your MBP is newer than your ”fancy new MP” just a FYI and we have the same Mac Pro’s and they aren’t new anymore. 6 years and counting

Yes....... I know... I know... what I meant was 'new to me'. My Mac Pro was an "upgrade" to me in every other way. It was admittedly naive of me to imagine that just because my Mac Pro cost £3,000 more than a Macbook Pro when new it would support three displays out of the box. I know better now and was merely hoping that another 6,1 user could show me the most cost-effective way of doing this i.e do I need to put an active dual-link adapter on one of the DVI displays, or both of them, or is there another work-around.

I know a lot people round here think the 6,1 is some kind of dinosaur but from my chair it's a Pro Tools rocket-ship and I love it. It cost me £2,000 second hand and was money well spent. I've checked and it out-performs the 5,1 12 core 64GB machine at the studio despite the latter having faster processors.

[Southsidemusic]

I agree with you that the 6.1 12 core rocks. We run 3 of them here and love them, I was just teasing you regarding the fancy new comment hehe No illmeaning as we have them too

I wish I could help you but we have 2 Slate Raven MTi2 screens on one studio and two Apple 27” 4K on the other and the 3rd has one Slate Raven MTX so none of them have 3 screens. I could try adding one of the 27” Apple screens for testing and see what happens.

I will post back as soon as I tried this.

[justinhill]

Originally Posted by Southsidemusic

I agree with you that the 6.1 12 core rocks. We run 3 of them here and love them, I was just teasing you regarding the fancy new comment hehe No illmeaning as we have them too

I wish I could help you but we have 2 Slate Raven MTi2 screens on one studio and two Apple 27” 4K on the other and the 3rd has one Slate Raven MTX so none of them have 3 screens. I could try adding one of the 27” Apple screens for testing and see what happens.

I will post back as soon as I tried this.

Thanks for the offer, Christopher! But I think from what I've read that my problem exists because I'm using DVI displays rather than mini-dp/Thunderbolt displays. My uneducated guess is that it must be something to do with the current the display adapters have to generate to drive DVI.

[Southsidemusic]

Aha. Got it!

I wish you all the best with this and hopefully someone else can chime in with better info than I can provide.

[justinhill]

Well shockingly I've got it working. In case anyone's interested, the problem is that although thunderbolt and mini-dp share the same connector, the power that thunderbolt provides isn't available over mini-dp, and there isn't enough juice to drive more than two DVI or HDMI displays.

I've been trying to find an Apple dual-link adapter without success (Apple don't sell them any more and there are very few on eBay etc.) and then I remembered I have a Belkin Thunderbolt dock I'm not using any more. It occurred to me that the thunderbolt "through port" on the Belkin might provide its own power.

And it does. Connecting the HDMI display using a mini-dp adapter but via the Belkin dock, it all works. Obviously this would be anything but a cheap solution if I didn't already have dock sitting around doing nothing.

[Southsidemusic]

Hey Justin

Thanks for the follow-up and solution so others here who might have the same question! Glad you got the screens running