How to connect 3 27inch ACDs to the MP with an AMD 5870 in it?

[chrono1081]

Hi guys.

I was planning on getting a hexcore MP with the ATI 5870 card and three 27inch Apple Cinema Displays, I saw that the card has two mini display ports but apples page suggests that you can only put one of these cards in the machine. Does anyone know if it will be possible to attach three monitors to one machine?

 

[Hellhammer]

Have both, 5770 and 5870 in it. Another option is to grab used GT 120 and use it along with 5870.

 

[chrono1081]

Cool thank you Hellhammer

Will the system automatically use the most powerful GPU for things like 3D modeling or would that be something I'd have to configure? I'm not too sure how the multiple graphics card thing works under Mac OS

 

[Hellhammer]

Cool thank you Hellhammer

Will the system automatically use the most powerful GPU for things like 3D modeling or would that be something I'd have to configure? I'm not too sure how the multiple graphics card thing works under Mac OS

I think the GPU in PCIe slot #1 is the main GPU, I guess that's the slot on the top. You can see the #1 GPU from System Profiler as well I think. Someone who owns Mac Pro can hopefully correct/confirm how to set up the 5870 as main GPU. It's not hard but I just don't know what slot it is

 

[Cindori]

the gpu used for work is the one that the screen is using.


example:


Screen 1 connected to 4870
Screen 2 connected to 5870

If a application window is displayed on the Screen 1, it will use the 4870. but if I drag the window over to Screen 2, it will start using the 5870 instead.


its very logical when you think about it.

 

[cutterman]

Sorry to threadjack, but I have a related question.

What is the best way to connect 2 30" ACD's to a 5770 card? Do I need to get the $99 dual link minidisplay port-to-DVI adapter for one and use the DVI port for the other?

 

[ventro]

the gpu used for work is the one that the screen is using.


example:


Screen 1 connected to 4870
Screen 2 connected to 5870

If a application window is displayed on the Screen 1, it will use the 4870. but if I drag the window over to Screen 2, it will start using the 5870 instead.


its very logical when you think about it.

What if you keep the app halfway between both monitors?

 

[Cindori]

I knew someone would ask that lol

the monitor with most % of pixels will keep rendering until the other monitor gets majority of pixels

if you try to drop the window dangerously close to 50%/50% then it will simply snap 100% to one of the monitors


I know too much about this machine...

 

[Dreadnought]

Sorry to threadjack, but I have a related question.

What is the best way to connect 2 30" ACD's to a 5770 card? Do I need to get the $99 dual link minidisplay port-to-DVI adapter for one and use the DVI port for the other?

The 5770 card has two minidisplay ports and one dual dvi port. So put 1 30" on the dvi port and one 30" on the minidisplay port with a connector from Apple, they're $29. Or buy two connectors and put both 30" on the minidisplay ports.
(In theory you can put 3 30" ACD's on one card. Would be nice watching a movie stretched over all three 30" ACD's (or bigger flatscreens). Can the card handle this??)

 

[Hellhammer]

The 5770 card has two minidisplay ports and one dual dvi port. So put 1 30" on the dvi port and one 30" on the minidisplay port with a connector from Apple, they're $29. Or buy two connectors and put both 30" on the minidisplay ports.
(In theory you can put 3 30" ACD's on one card. Would be nice watching a movie stretched over all three 30" ACD's (or bigger flatscreens). Can the card handle this??)

The 29$ adapter is single-link and is limited to 1920x1200. To run resolutions greater than that, you need the 99$ dual-link DVI adapter.