Crossfire in 2006 Mac Pro

[vstep]

I have a 2006 Mac Pro and I'm wondering if CrossFireX is possible on this system. Specifically with two 5770s.

My understanding is that CrossFireX requires two PCIe 2.0 16x slots. However, the 2006 Mac Pro only has PCIe 1.x slots, and with two cards, it's only possible to have its slots running at 8x. Does this prevent CrossFireX from working at all, or is it simply a case of it working fine but running at reduced performance?

Anyone know?

[Hellhammer]

I don't think the speed of the slots is crucial as long as both GPUs are recognized. You can't run CF under OS X but it should work fine under Windows

[vstep]

I don't think the speed of the slots is crucial as long as both GPUs are recognized. You can't run CF under OS X but it should work fine under Windows

Thanks. Yeah, just looking to CF in Windows only. Pretty sure both GPUs will be recognized. The machine has the capacity to hold and power two double-wide cards.

I guess I'll place an order for two 5770s now.

[Cindori]

it will work fine, but expect 5-15% performance loss because the cards need to be run in 8x / 8x PCIe 1.0

[chych]

Nevermind delete me

[vstep]

it will work fine, but expect 5-15% performance loss because the cards need to be run in 8x / 8x PCIe 1.0

Thanks Cindori.

Since CF is Windows only, is it possible then to use one Apple 5770 card and one cheaper 5770 PC card, or does Crossfire work more favorably if the two 5770s are exactly the same?

[Cindori]

Thanks Cindori.

Since CF is Windows only, is it possible then to use one Apple 5770 card and one cheaper 5770 PC card, or does Crossfire work more favorably if the two 5770s are exactly the same?

when the apple 4870 came, crossfire did not work with that card. it was not until a windows driver (catalyst) update 4 months later that the apple cards suddenly started working with crossfire. it was wierd. I recall that crossfire worked fine on PC flashed cards though (before the catalyst update).

I don't know if the apple 5000 cards are working with crossfire right now.

[ActionableMango]

when the apple 4870 came, crossfire did not work with that card. it was not until a windows driver (catalyst) update 4 months later that the apple cards suddenly started working with crossfire. it was wierd. I recall that crossfire worked fine on PC flashed cards though (before the catalyst update).

I don't know if the apple 5000 cards are working with crossfire right now.

Anyone able to verify this yet?