Two gpu's on 3,1

You should be able to do that. I'm not sure if the 2600 is a double wide card, but if not, you may need to move it and put the 5770 or 5870 in the double wide slot.

The 2600 is not a double-wide card.

OP: The 5770 and 5870 can drive three monitors, so you may be able to ditch your 2600. There are some limitations: http://support.apple.com/kb/HT4279
This may help you figure out which PCI-E slots to use: http://support.apple.com/kb/HT2838

if none of your displays are DP, get a 5770 and run 2 dvi monitors off it


else, if u have DP displays, get 5870 and sell your 2600. most powerful alternative, and allows triple monitor setup

Cindori said:

if none of your displays are DP, get a 5770 and run 2 dvi monitors off it


else, if u have DP displays, get 5870 and sell your 2600. most powerful alternative, and allows triple monitor setup

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The 5770 allows triple monitor setups as well. The output constraints are identical for 5770 and 5870.

FroColin said:

Wait... This doesn't make sense to me. Sorry. Why can't I get a DP to DVI adaptor and use three monitors with the 5870 (Or the 5770 for that matter as they have the same outputs).

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Because:

phairphan said:

OP: The 5770 and 5870 can drive three monitors, so you may be able to ditch your 2600. There are some limitations: http://support.apple.com/kb/HT4279

Click to expand...

However, in case that you have displays smaller than 2560x1440, you'd only need active single link miniDP - DVI (check amazon) adapters.

Performance wise, triple displays on a single card are not a problem unless you need all the available VRAM for heavy graphic applications.

Transporteur said:

The 5770 allows triple monitor setups as well. The output constraints are identical for 5770 and 5870.

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ofc, but he probably wants a good performance gpu.

Cindori said:

ofc, but he probably wants a good performance gpu.

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I wouldn't say that the 5770 isn't under performing.
It's a solid desktop card which suffices the vast majority of applications. Apparently, gaming isn't really what the 5770 is made for, but who games anyway?

Personally, I wouldn't waste $400 for a 5870 if my only needs are word processing and stuff like that.

FroColin said:

Hmmmm I read somewhere that you couldn't run three displays off either card on a 3,1 mac pro. Was that wrong?

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I am running a triple-head 5770 in a 2008 MacPro (3,1) along with a second card with 2 heads. Works fine. I don't know if the $100 adapter is required all the time, but I am using it on two of the displays and the $30 adapter on another display.

You can add the 5770 and still use up to three of the 2600s. The 1st slot is a double wide slot, so installing the 5770 there, or any other double wide card still leaves all three remaining PCI slots available. If you want to add two new (double wide) cards, then you do lose a PCI slot, but you'd still have two remaining for your two 2600s.

You only need the active DP adapter if you're running dual-link DVI. If you're not running a 30" monitor or its equivalent, then a passive link adapter works fine. I've seen a lot of discussion about three monitors being pretty unstable with the 5770, even beyond Apple's technical notes, so I'd probably avoid that setup unless you really have to use it for some reason. With a 5770 and two 2600s, I can't see how you would...

Stephen23 said:

You only need the active DP adapter if you're running dual-link DVI. If you're not running a 30" monitor or its equivalent, then a passive link adapter works fine.

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That's only halfway correct.
You only need Apple's active dual link DP if you have to run dual-link monitors such as 2560x1440 or 2560x1600.
If you run a triple screen setup with three DVI monitors, two of which do not require dual-link DVI, you need active single link DP adapters.
For a dual screen setup with a single link screen connected to the outer most display port, the passive single link adapter Apple sells works just fine.