User profile for user: David Mahony
David Mahony Author
User level: Level 1
9 points

Mac Pro 3.1 not booting after ram install

Hi Everyone,


Before my troubles started I had 2x2gb in riser board A and 2x2gb in riser board B and everything was working fine.

However today I came to install 2 new 4gb modules by placing them into slots 1 & 2 of riser B and placing the 4x2gb modules into riser B and now it's all gone horribly wrong!😟


When I turned on my mac the fans went into overdrive but i still managed to get into my account but could only see 8gb of the 16gb installed.

I then shut down took out the new 4gb modules put back everything back as before and restarted but this time it powered up but there wasn't even a boot sequence!


I've tried switching the boards around and even tried an SMC reset but all to no avail .


I'm totally stuck and not sure what to do next can anyone please help?

OS X El Capitan (10.11.3), Nvidia Geforce GTX 670 • BenQ FP241W

Posted on Oct 6, 2016 9:51 AM

Reply
22 replies
User profile for user: lllaass
lllaass
User level: Level 10
210,519 points

Oct 6, 2016 10:02 AM in response to David Mahony

What are the details of the old memory (Original?) and of the new memory?

Sounds like the old and new memory are not compatible when both installed.

MPs originally came with ECC (Error Correct Code) memory installed and big heat sinks with temp sensors.

Some replacement memory is non-ECC (You can't mix ECC and non-ECC memory but can use ether as long that is the only memory used). Some replacement memory does not have large heat sink or temp sensors. If no temp sensors the fans can run at full speed as default.

Reply
User profile for user: David Mahony
David Mahony Author
User level: Level 1
9 points

Oct 6, 2016 11:29 AM in response to Eau Rouge

Well I thought I'd purchased the correct ram, the guy I spoke to assured me that it was!

All the details in the invoice and labelling on the module suggest all is in order.


Further update...


I've now moved the ram in riser A into slots 3 and 4 and my mac appears to be back to normal 🙂!


So to summarise I have the ram now positioned as follows:


Top riser:

2gb into slot 3 and 2gb into slot 4


Bottom riser:

2gb into slot 3 and 2gb into slot 4


BUT how do I now go about installing the 2 x 4gbmodules without my 'warhorse' going belly up?!

Reply
User profile for user: lllaass
lllaass
User level: Level 10
210,519 points

Oct 6, 2016 12:42 PM in response to David Mahony

This is what real compatible memory looks like. Note the big heatsinks

http://www.newegg.com/Product/Product.aspx?Item=9SIA6HY41C7151&nm_mc=KNC-GoogleM KP-PC&cm_mmc=KNC-GoogleMKP-PC-_-pla-_-Mac+-+Memory-_-9SIA6HY41C7151&gclid=Cj0KEQ jw7Ne_BRDRmP2ojKfzv98BEiQAPuqPyUbA-8OAz_Oy50EEDhpsGA3sxUAWEMLahNQPScMV-s8aAkzp8P 8HAQ&gclsrc=aw.ds

Does the old memory look like that?

The link you provided for the new memory does not look like that.

The memory in your link look like standard FB-DIMM PC server memory

Reply
User profile for user: David Mahony
David Mahony Author
User level: Level 1
9 points

Oct 6, 2016 1:10 PM in response to lllaass

Ok here's what's happened...

As suggested earlier I put the the new modules into slot 1 of both risers and the Mac booted to the login screen BUT, the fans were now running at full blast!

Youre right about the heatsinks heres some photos of what I have...

https://www.dropbox.com/s/mlundu3goo64xks/Old%20Ram.jpeg?dl=0

https://www.dropbox.com/s/2hvh96eelmpd06b/New%20Ram.jpeg?dl=0

Old ram on the top link and new ram on the other....sorry I could get photos to upload.


Maybe it is I have the wrong type of ram?

Reply

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Mac Pro 3.1 not booting after ram install

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.
Learn more Sign up