Dear Mac Pro forum,
as the HD 5770 I have put in my upgraded 2006 Mac Pro starts to get pretty limiting, I am looking to replace it with some faster card. The perfect candidate seems to be a R9 280x (El Capitan support, good deals on my local marketplace). The issue is it's hunger for power. I've read about shutdowns on high GPU loads and even the compatibility list wikipost recommends additional power. Therefore, I would like to perform the popular "Pixlas mod". The house of moth tutorial has some schematics for 1,1 to 3,1s. I've already seen those confirmed to work on 3,1 Mac Pros by a few people and even found some photos. But while the info on 3,1s is scarce, on 1,1/2,1s it is inexistent. As I don't know which pin is the trickle power, I can't measure the voltages myself in fear of causing damage. When it comes to compatibility of power supplies between the 2006 and 2008 models, I also heard about the 1,1s having lower amperage, resulting in problems for people who upgraded to 3,1 logic boards.
as the HD 5770 I have put in my upgraded 2006 Mac Pro starts to get pretty limiting, I am looking to replace it with some faster card. The perfect candidate seems to be a R9 280x (El Capitan support, good deals on my local marketplace). The issue is it's hunger for power. I've read about shutdowns on high GPU loads and even the compatibility list wikipost recommends additional power. Therefore, I would like to perform the popular "Pixlas mod". The house of moth tutorial has some schematics for 1,1 to 3,1s. I've already seen those confirmed to work on 3,1 Mac Pros by a few people and even found some photos. But while the info on 3,1s is scarce, on 1,1/2,1s it is inexistent. As I don't know which pin is the trickle power, I can't measure the voltages myself in fear of causing damage. When it comes to compatibility of power supplies between the 2006 and 2008 models, I also heard about the 1,1s having lower amperage, resulting in problems for people who upgraded to 3,1 logic boards.