Mac Pro 2006 and Expansion Slot Utility

[whwh1776]

Hi All,

Requesting assistance with Expansion Slot Utility on a 2006 Mac Pro. Below is the specs, my goal is run the AMD 6870 at its max speed, at x16. When I select option 1 and 2 in the utility's alternate PCI Express Profiles (see attached picture), and reboot, the AMD 6870 isn't recognized and screen remains blank, the HD 2600 is functional. I tried removing the HD 2600 and still had the same results. I also try different version of OS X, didn't make any difference. Am I missing something?

Lastly, I have been considering moving up to a AMD 7950 (7970) or GTX 680; seems pointless if it will be struck at 8x.

Mac Pro 2006

• Processors upgraded to 2 x 3.0 Ghz Quad Core
• Fireware flashed to 2,1
• GPU 1: AMD HD 6870 1GB (non-flashed, no boot screen) in slot 1
• GPU 2: Apple ATI HD 2600 256MB in slot 3
• Monitor: Apple 30" cinema display

Running the following OS on 3 different hard drives :

• OS X 10.7 Lion
• OS X 10.10 Yosemite
• OS X 10.11 El Captain

 

[owbp]

Hi,
Are you able to run HD2600 at x16 in 1st slot?
There may be problems with physical lanes themselves on your card (if you're able to run HD2600 at x16) or in your PCI slot (if no card wants to run at x16).
I had HD6850 in my Mac few months ago and it ran at x16 with no problem.

HD7950/70 aren't that expensive right now and they're great and powerful cards to have in cMP 2006/07.
You can easily flash them for bootsreen (6850/6870 can't because they have 64 EFI only) and you can go nuts in Bootcamp in Full HD resolution.

Btw, there isn't much difference between x16 and x8 in real life usage, so i wouldn't worry about that so much.
Look here for example - as you see, much smaller difference than 50Hz of clock.

 

[whwh1776]

Thanks owbp, I'll try to place the HD 2600 in slot 1 tomorrow and see what happens.