Mac Pro 3.1 shows only Ram B1 and B3

[Langkampfen]

Got me a while back a Mac Pro 3.1 with 320 GB Harddrive and 4 GB Ram.
Had a Stick with 2 GB on A1 and 1 on B1 (all OK
Got me some used Ram and put on A1 and A2 2 GB each. On B1 and B2 1 GB, and A3 & A4 & B3 & B4 512 Mhz each
It only showed up 5 Gb on Rise a. Riser B was shown as empty
I removed all 4 512 Mb Ram and it only showed 1 GB on B1
Now i ordered 16 GB from Amazon. 2 Gb each Stick from one Seller and each the same Lebel on.
Mac only is showing 2 GB on B1 and B3 too. All other shown as empty.
I swapped the Riser with same Result.
I remove Riser A and Light on Boot Button is flashing (not booting)
In that Case the Ram on Riser A musst be recognised,otherwise it wouldnt boot.
The only other Thing what i did was upgrate of El Capitan from 10.11.4 to 10.11.6 between all OK and not recognising some Ram.
Its a early 2008 8 Core 2.8 ghz with 960 Gb Crusial SSD
Thanx for your Time

 

[handheldgames]

Hmmmm. any dust build up? Have you swapped ram riser positions?

Sounds like a stack of mixed working / failing Ram. is everything the same speed / type / chip manufacturer?

Try 2 dimms in a1/b1. If successful, remove ram and set aside and repeat to verify ram. after having know working ram, From there id test a full stack of tested ram each card.

it ccould be the new ram, a ram riser failing, or even a tired power supply.

 

[Langkampfen]

Hmmmm. any dust build up? Have you swapped ram riser positions?

Sounds like a stack of mixed working / failing Ram. is everything the same speed / type / chip manufacturer?

Try 2 dimms in a1/b1. If successful, remove ram and set aside and repeat to verify ram. after having know working ram, From there id test a full stack of tested ram each card.

it ccould be the new ram, a ram riser failing, or even a tired power supply.

Hi. thanx for quick Reply.
I got used Ram and,yes. I swaped Ram and i swaped Riser and it just recognises B1 and B3.
Before i had that Problem i updated El Capitan from 10.11.4 to 10.11.6 but have no Hardware Test on it. Boot with holding D or Option and D is unsuccessful.
So,Riser cant be faulty as it works when i swap it and Riser A was recognised before OSX update. Otherwise i would have ordered a other Logicboard on Ebay.

 

[TonyK]

Any updates? I have a 3,1 but still running 10.10. Just too many concerns about 10.11 and now between this and USB issues I've read about not sure I will upgrade. May even downgrade the 2 laptops to 10.10 from 10.11.

 

[nigelbb]

I have had a couple of 2008 Mac Pro 3,1s from new & almost every time I have ever done any reconfiguration of the RAM it has required multiple reseating of the RAM & risers before all the RAM was recognised. Once it was all working it stayed working you just need to persevere.

667MHz FB-DIMMs pulled from Dell & HP Xeon servers can be bought cheap on eBay. 32GB can be found for as little as $50-$60. Performance is all but identical to that of the Mac only 800MHz parts with massive heat sinks although even these parts are much cheaper than the used to be $100-$150 for 32GB. I suggest getting some new FB-DIMMs & carefully cleaning all contacts.

 

[NY Guitarist]

I can add +1 to the data for having to reseat riser cards. At one point I had to reseat them a few times to clean the connectors; haven't had a problem since.

 

[TonyK]

My own 2008 has been upgraded for memory multiple times and I've not had any issues.