Help to Crossfire with ATI Radeon HD 5770 x2 for Windows on Mac

[timidhermit]

It was suggested to me by other forum members to repost my previous thread on this subforum to seek better help with my questions:

https://forums.macrumors.com/thread...-ati-radeon-hd-5770-x2-on-macpro-5-1.1895954/

There is the original post:

I have a Mac Pro 5,1 with a stock ATI Radeon HD 5770.

I recently purchased another genuine Apple (not Apple-flashed) ATI Radeon HD 5770 and installed it in the Mac Pro.

Both cards are working fully and independently on Yosemite and on Windows 7.

I want to now set up the two cards using Crossfire to use for both Mac and Windows (dual boot).

My questions:

1. Is it possible to crossfire two stock genuine Apple ATI Radeon HD 5770? Both cards have fingers that are seemingly for the Crossfire bridge connectors.
2. Where do I buy the Crossfire bridge connectors? Does ATI or Apple sell the bridge connectors for 5770? Is the bridge connector different for the different models?
3. I am using the BootCamp driver 5.1.5621 that has built-in ATI Catalyst driver support. Is this sufficient to run Crossfire?

 

[ActionableMango]

Bootcamp drivers are typically much older than drivers direct from AMD, so you should download AMD's catalyst drivers and in the settings, enable crossfire.

IIRC, you don't need a bridge connector for two 5770s as it didn't really help performance, but I could be remembering that incorrectly and thinking of a different model.