Mac Pro and multiple monitors

For more than two display using legacy connections like DVI, you have to use an active adapter.

If the resolution is less than 1920X1200 as your case, the $99 dual-link adopter is not required. A active adopter like

http://www.startech.com/AV/Displayport-Converters/Mini-DisplayPort-to-DVI-Active -Adapter~MDP2DVIS

http://www.amazon.com/Accell-B087B-006B-2-DisplayPort-Single-Link-Certified/dp/B 0098HVZA0/ref=sr_1_3?ie=UTF8&qid=1421443…

is ok

See:

Mac Pro (Late 2013): Using multiple displays - Apple Support

The Apple adopter is a passive adapter. For more than two legacy monitors you need an active adapter for the third and subsequent monitors, For your three monitors you only need to replace one Apple adapter with one active adapter

Hi,

This can't be true, I'm running 10.10.3 on a Mac Pro 3,1 (early 2008). This has 2 NVIDIA GeForce 8800 GT card installed in it with two monitors attached to each (4 in total).

I originally had 3 monitors each running at 1920 x 1200 @ 60 Hertz (NTSC), this worked fine. Today however I added a 4th monitor. The 3 original monitors are all Samsung 24A450's, the new one is an updated version of the same monitor - Samsung 24C450. When the monitor arrived, I shut down the Mac Pro, then attached the monitor and powered up again. When it started up, only two monitors were showing. After trying a couple of things, I shut down again and disconnected the new monitor and power up again, all 3 of the originals came back up. I then tried connecting the 4th Monitor (the 24C450) while the machine was still running and low and behold it recognised it! I configured it and it seems to work ok.

I have one remaining (minor) problem with it, the 3 original Monitors have resolutions of 1920 x 1200, but the newer monitor won't go above 1920 x 1080. Why is this? Is it possible to get this new monitor to match the 1920 x 1200 resolutions? If I got an active adaptor would this make it use the higher resolution. I'm connected via DVI on all four, is it a cabling issue? I am using the cable that came with the 4th monitor, but have another one on order which I'll try when it arrives.

So, unless you've solved the problem using active adaptors, you could try connecting the DVI to the machine while it is still running.

All the Best

Dave

From the original post:

I have a new Mac Pro (Late 2013)

Nothing to do with "Classic" Mac Pro with 8800.

There are also "rules" for the Apple ATI 5770. Another subject.

The AMD D300 thru 700 do not have legacy DVI, like your 8800.

You are going DVI to DVI.

Sorry, I misread the original post.

I am having a similar issue. I have the 2013 Mac Pro. I have 2 Samsung 27" monitors and 1 Samsung 32" TV. They were previously hooked up to a 1st gen Mac Pro 8 Core with an unsupported AT 5870 that had 2 md ports and a dvi port. I had 2 apple active dvi adapters for the 27" and an HDMI to DVI cable for the TV.

The chain goes like this, 27" Samsung monitor with HDMI to DVI cable running from monitor to Apple Dual Link DVI adapter with additional usb power and plugged into the mini display/tb port. X2.

Now that I have the 2013 Mac Pro I connected the 2 monitors via Apple DVI to TB ports and the TV with HDMI to HDMI cable. It only displays 2 most of the time. I tried changing the HDMI to HDMI cable with an HDMI to mini display port cable. It only displays 2 most of the time.

I bought a 3rd Apple Dual Link DVI adapter and connected it the same as stated in the chain above. It worked for a little bit. Now it only displays 2. Not sure exactly what the issue is.

All are connected to separate TB buses. Could it be that the monitors actually have to have a DVI connector instead of just HDMI or VGA?

Any help would be greatly appreciated.

More than two "Legacy" displays requires the use of ACTIVE adapters. If the adapter has a USB pigtail, it must be connected, because it is used to pick up even more power to run the converter.

The built-in HDMI, if you use it, counts as one of your "Legacy" connections.

Grant, thank you for responding. I do have 3 Apple branded active adapters connected. All 3 usb pigtails are plugged into 3 12 watt Apple usb chargers. I also tried connecting them directly to a powered usb hub as well as the usb3 ports on the mac pro itself. It didn't change anything. My first attempts included using the HDMI port but I am running all to the TB ports now.

So current chain is 3 monitors, 3 HDMI to DVI cables. HDMI to monitors, DVI to the 3 Apple active adapters (these are the $99 Apple active dual link dvi adapters http://store.apple.com/us/product/MB571Z/A/mini-displayport-to-dual-link-dvi-ada pter), usb pigtails connected to 12 watt Apple usb chargers and mini displayport plugs from active adapters into 3 thunderbolt ports on mac pro each connected to a separate bus.

The weird thing is, once I boot up, if i disconnect all 3 plugs one at a time, all the monitors light back up and work properly. Even waking from sleep they still work properly. But if I shut down or restart, only 2 displays light up. Once in awhile they will all light up, but other than that I have to unplug all three mdp plugs to get them to work again.

I dont necessarily mind unplugging them to get it all to work, I'm just concerned that daily plug/unplugging will wear down the plugs and the ports quickly.

Again, thanks for the response Grant