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MattsanaX

macrumors newbie
Original poster
Mar 27, 2012
20
1
Gothenburg, Sweden
There are two red lights showing by the RAMs (Got dual CPU version).
However there are no signs of errors in the OS X at all. However sometimes when I boot I get a blue screen but if I wait it out then it corrects the error code and continues to boot perfectly after a few minutes. It's been like this before I switched all RAM modules. However the boot problem has existed since before the red lights appeared. So I cannot figure out what this might be!

Does anyone have a clue?
 
Try switching some of the RAM modules around, make sure the risers are well connected to the logic board. I recently had this issue when swapping the RAM in my Mac Pro, but I just had to move some stuff around and it's working fine now. If the issue persists, you may have an issue with the RAM modules or the risers - try isolating the issue by removing the RAM modules one by one, etc.
 
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The Mac Pro 4,1 and 5,1 don't use memory risers as the earlier gen Mac Pros do... RAM resides on the same board as the processors in this case. As r6mile suggested, move the RAM bars around and ensure they are reseated securely in place.

Before moving the RAM bars, take note which RAM is giving errors and see if those errors move with the respective RAM bars after you move and reseat them. If they do then you have the source of your issues. Good luck.
 
How do I know which ones give the error? There are 1 light per 4 slots. I've also done some stress test with AIDA and it shows nothing.
 
How do I know which ones give the error? There are 1 light per 4 slots. I've also done some stress test with AIDA and it shows nothing.

The led indicators number is usually dependant on the cores installed on your system. i.e. 8 core models have 8 leds as i notice on their diagrams.

Apple states that <An illuminated, red LED indicates its associated DIMM may be poorly seated or failed.>
see screenshots for some exceptions etc. if they are of any help to you.

did you try looking for the respective macpro service manual over the web ?
I can pass my early 2009 manual to you and have a go if you like. Page 17 and further down has lot of info. i attach some screenshots for you.
 

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There are two red lights showing by the RAMs (Got dual CPU version).
However there are no signs of errors in the OS X at all. However sometimes when I boot I get a blue screen but if I wait it out then it corrects the error code and continues to boot perfectly after a few minutes. It's been like this before I switched all RAM modules. However the boot problem has existed since before the red lights appeared. So I cannot figure out what this might be!

Does anyone have a clue?

Take it to the Genius Bar, they'll diagnose it and service it for you if necessary.
 
Hello again guys. The weird thing is that everything works well and I can stress the computer during rendering without any hickup. I'm just curious to know why they lit up. I've tried reseating the RAM and I tried reinstalling my old 12GB ram that I had before. Same thing lol. Very strange.
 
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