ATI Radeon HD5770 not working on Mac partition

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ATI Radeon HD5770 not working on Mac partition

I have a Mac Pro 3:1 (early 2008). The orirginal 2600XT graphics card that came with it broke so I replaced it with a flashed HD5770. This worked fine for a while (except for the HDMI output didnt seem to work properly). The majority of the programs that I use now are windows only so I have set the computer to automatically run windows at startup - this works with no problem. However when I try to choose my startup disk (by holding alt at startup) to get onto my original mac partition I get nothing from the graphics card at all. I have tried all of the different outputs and also tried resetting the PRAM.

I urgently need to resolve this as I am having to sell this computer to upgrade as soon as possible.

Any help would be greatly appreciated.

[Edit: My Mac parition is running Snow Leopard 10.6.3]

Mac Pro

Posted on Mar 17, 2014 6:04 AM

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Answer 1

markwmsn

Level 6

14,987 points

Mar 17, 2014 7:14 AM in response to ThatJoeThom

As I understand things from discussions in this forum, that behavior is precisely why people recommend installing only genuine Apple HD5770s instead of flashed PC versions. Unfortunately, knowing that doesn't help you now.

I don't know that this will help, because I don't know at what point in the boot process the code will be able to use the flashed card, but have you tried booting from the Snow Leopard installer disc (holding down "C" instead of alt/option)?

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Answer 2

Mar 17, 2014 7:26 AM in response to markwmsn

markwmsn has stated that information correctly. These cards:

RE: Mac Pro silver tower (2006-2012) Replacement Graphics cards

1) Apple brand cards,

2) "sold in the Apple store" cards, and

3) "Mac Edition" cards ...

... show all the screens, including Boot up screens, Safe Mode, Installer, Recovery, debug screens, and Alt/Option boot screens.

OTHER CARDS often do not.

User Tip: Mac Pro silver tower (2006-2012) Replacement Graphics cards

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