Hello all.

I hope users with great knowledge about HW can help me with this issue.

I bought Mac Pro for my music studio to work with audio.


Mac Pro "Quad Core" 3.7 (Late 2013) 3.7 GHz Q. Core Xeon E5-1620v2

Intro. October 22, 2013* Disc. April 4, 2017**
Order ME253LL/A Model A1481 (EMC 2630)
Family Late 2013 ID MacPro6,1
RAM 64 GB (was 16GB) VRAM 2 GB
Storage 256 GB SSD Optical None*

I was having random crashes in Logic Pro - beachballing on screensaver wakeup etc.
I decided to test my rams with memtest86. Straight away i got many errors and without hesitation assumed they are bad and replaced them (as I was about to upgrade them anyway).
But the problems remain. System is not stable and every now and then I get crashes and freezes.

Now I test each ram seperately and the results are..

RAM 1 SLOT 1 TEST 10 3078 errors
RAM 1 SLOT 2 TEST 10 3078 errors
RAM 1 SLOT 3 TEST 10 3078 errors
RAM 1 SLOT 4 TEST 10 3078 errors

RAM 2 SLOT 1 TEST 10 3078 errors
the rest are being tested still...

I run on board diag "D" on startup - and it shows no issues found.

I contacted RAM supplier and they advised that all modules were tested and there is no way all 4 are bad. And most likely my CPU or CPU Riser Card is faulty. (seems to be common issue with these Macs)

Can anyone advice how can I figure out the faulty part to be able to replace it. Is there a way to test Riser Card? can CPU tests tell anything?

I will appreciate any support and will be responding to any suggestions / questions.