I recently acquired a Mac Pro (3,1) 2008.
When I first booted it, it detected 20GB ram (2,2,empty,empty / 4,4,4,4). Then I decided to physically check the Ram, and found that those two empty slots were actually 2x 4GB sticks. I decided to mess around with the Ram sticks to get the full 28GB detected. But to my frustration, when I returned the Ram back exactly as it had been, it now only detected 4GB (2,2,e,e / e,e,e,e).
After multiple ram swaps and tests, I managed to get it back to a respectable 12GB (2,2,4,4 / e,e,e,e), but cannot get the bottom riser to detect anything.
Every time I populate the lower riser now, regardless of which ram pairs I use (including those confirmed to work in the upper riser), I get (e,e,e,e) and a red light error in Dimm 1.
It’s not a problem with the riser, because I tried swapping risers. Whichever one I put in the lower slot has this problem – four empty slots and a red light for Dimm 1.
What could be the problem and solution for this?
TLDR: Had a working 20GB ram (with 2 4GB pairs not detecting). When I had a look at the risers and then reseated, I could no longer get to 20GB anymore (only 12), and there is a red light error in Dimm-1 in either lower riser.
When I first booted it, it detected 20GB ram (2,2,empty,empty / 4,4,4,4). Then I decided to physically check the Ram, and found that those two empty slots were actually 2x 4GB sticks. I decided to mess around with the Ram sticks to get the full 28GB detected. But to my frustration, when I returned the Ram back exactly as it had been, it now only detected 4GB (2,2,e,e / e,e,e,e).
After multiple ram swaps and tests, I managed to get it back to a respectable 12GB (2,2,4,4 / e,e,e,e), but cannot get the bottom riser to detect anything.
Every time I populate the lower riser now, regardless of which ram pairs I use (including those confirmed to work in the upper riser), I get (e,e,e,e) and a red light error in Dimm 1.
It’s not a problem with the riser, because I tried swapping risers. Whichever one I put in the lower slot has this problem – four empty slots and a red light for Dimm 1.
What could be the problem and solution for this?
TLDR: Had a working 20GB ram (with 2 4GB pairs not detecting). When I had a look at the risers and then reseated, I could no longer get to 20GB anymore (only 12), and there is a red light error in Dimm-1 in either lower riser.