More monitors for Mac Pro

[danox574]

I have a Mac Pro 4,1 with a Radeon 4870 which I understand I can support 2 monitors. I currently have a 24" Cinema display plugged into its display port. I'm going to be getting some retiring hardware coming my way and will score 1-2 more 24" Cinema displays. I'd like to line them up and create Megadesktop.

First I went looking for DVI to Displayport adapters for Montior #2. Normally I'm pretty skilled at this Interwebs thing, but I couldn't find a single adapter. They seemed to go other way every time I got a search hit. Can this be done?

I could upgrade my 4870 to a 5870 and get dual display ports available to me for that card, correct?

Then, I went looking for a PCI-E video cards to plug into my open slots for monitor #3, or if I can't run two of these off the 4870, a pair of video cards with display port out. All I could find was the large, double cards that needed extra power, much like my 4870. Do any cards exist that take up a single slot? I thought I saw some Geforce GT120 refurbs -- anything newer?

Am I barking up the wrong tree to run 1 or 2 additional 24" Cinema Displays?

 

[iBookG4user]

IIRC there isn't a way to connect a Mini Displayport monitor to DVI through an adapter.

 

[CaptainChunk]

You can actually convert a DVI-D signal to MDP with one of these two adapters:

Single-link (up to 1920x1200)
Dual-link (up to 2560x1440)

But as you'll see, they're far from cheap and you would need two of them. A couple of used Apple GT 120s would probably cost around the same or less, and going that route would carry the advantage of each display getting a dedicated frame buffer. That's assuming you have the slots to spare, of course...

 

[ClassObject]

I run 4 1080p monitors on an ati 6870. I used to run the same 4 on a gt8800 and a gt120. My suggestion is a 6870 or better with 2 active mdp, 1 hdmi or dvi (both if you want four monitors). If you want apple supported cards, get any of the apple cards in addition to what you already have.

 

[CaptainChunk]

I run 4 1080p monitors on an ati 6870. I used to run the same 4 on a gt8800 and a gt120. My suggestion is a 6870 or better with 2 active mdp, 1 hdmi or dvi (both if you want four monitors). If you want apple supported cards, get any of the apple cards in addition to what you already have.

But considering the OP's situation, which would be potentially 3 total 24" ACDs (MDP only) to drive, I don't think there's anything on the Mac side that would accomplish that on a single card due to driver limitations.

So, I'm pretty sure that leaves either using expensive active adapters like the ones I previously linked or adding cards with DP/MDP ports (preferably ones that don't require external power, since his existing 4870 already occupies both feeds) to drive the other two displays.