RAM not showing

The System Profiler in my Mac Pro 3,1 2.8Ghz (early 2008) shows that all four DIMMs in the A memory card are empty, but they are not. Both cards are full (4 x 2GB each). I first switched them, and the profiler continued to read that the A card was empty . I returned them to their original position, and it still reads that all four A card slots are empty. I ran a hardware test, which recognized all eight DIMMs and reports that they are functional.

A) Should I assume then that all 16GB are functional?

B) Any idea why the system profiler isn't recognizing the A card DIMMs, and how can I correct this problem?

Are you sure you bought ECC, fully buffered DIMS?

I didn't actually add any, 16GB original RAM; just recently discovered that only 8 are showing in the profiler.

Boot you're MAC in the verbose mode .
See if you can find in the beginning of the boot process the next 2 messages :
PAE enabled
64 bits mode enabled .

Both PAE enabled and 64 bit mode enabled show when in verbose mode

Will you give the command in Terminal system_profiler .
Supposing that you normally use the Gui and not the commandline .
The command gives a very detailed info .
Scroll along it to find the info you are looking for

rexk said:

I didn't actually add any, 16GB original RAM; just recently discovered that only 8 are showing in the profiler.

Click to expand...

Since this is a 2008 Mac Pro...what is it's history? Have you owned it since 2008...or did you buy it used recently?

Ram for Mac Pro's can be "picky"...so it must be the correct type of ram. If you bought it used...maybe the previous owner installed the wrong ram.

If you go to the Apple Drop-down menu...and choose "About This Mac"...how much ram does this window say the computer has?

- Nick

p.s. If "About This Mac" only reports 8 gig of ram...there is also a very special way that ram must be installed in Mac Pro's (matched pairs...and in the proper slots). So even though the Mac Pro has all eight ram slots full with 2gig DIMMS in each & every slot...maybe there are slight differences in the ram that makes them "not matched".

Just thinking of any reason why all 16 gig is not being recognized.

dobby said:

Will you give the command in Terminal system_profiler .
Supposing that you normally use the Gui and not the commandline .
The command gives a very detailed info .
Scroll along it to find the info you are looking for

Click to expand...

Please explain further - I can follow basic instructions, but don't understand these comments.

pigoo3 said:

Since this is a 2008 Mac Pro...what is it's history? Have you owned it since 2008...or did you buy it used recently?

Ram for Mac Pro's can be "picky"...so it must be the correct type of ram. If you bought it used...maybe the previous owner installed the wrong ram.

If you go to the Apple Drop-down menu...and choose "About This Mac"...how much ram does this window say the computer has?

- Nick

p.s. If "About This Mac" only reports 8 gig of ram...there is also a very special way that ram must be installed in Mac Pro's (matched pairs...and in the proper slots). So even though the Mac Pro has all eight ram slots full with 2gig DIMMS in each & every slot...maybe there are slight differences in the ram that makes them "not matched".

Just thinking of any reason why all 16 gig is not being recognized.

Click to expand...

Bought slightly used in late 2008, but think RAM DIMMs are all original; appear identical, and as I said initially, switching cards shows that card B is recognized regardless of which card is in it. Also, Hardware test says all RAM accounted for and functional.

rexk said:

Bought slightly used in late 2008, but think RAM DIMMs are all original; appear identical, and as I said initially, switching cards shows that card B is recognized regardless of which card is in it. Also, Hardware test says all RAM accounted for and functional.

Click to expand...

So you're saying that you've had this computer since "late 2008"...and now in early 2012 you finally notice this "little detail"???

Anyway...you didn't answer my question about what does "About This Mac" report regarding how much ram is in the computer.

Another place to check...go to your:

- Applications Folder
- Utilities Folder
- open the "Activity Monitor" application
- click on the "System Memory" tab near the bottom of the window

How much ram is reported below the multi-colored "pie chart"?

- Nick

If you run the command I suggest among a lot of other info it also gives you info of the DIMM like :
Size :
Type
Speed
Status
Part number
Serial

Empty DIMM if there are any empty DIMM

pigoo3 said:

So you're saying that you've had this computer since "late 2008"...and now in early 2012 you finally notice this "little detail"???

Anyway...you didn't answer my question about what does "About This Mac" report regarding how much ram is in the computer.

Another place to check...go to your:

- Applications Folder
- Utilities Folder
- open the "Activity Monitor" application
- click on the "System Memory" tab near the bottom of the window

How much ram is reported below the multi-colored "pie chart"?

- Nick

Click to expand...

RAM showing under pie chart is only 8GB; how did hardware test see all 16 and deem them functional?

rexk said:

RAM showing under pie chart is only 8GB; how did hardware test see all 16 and deem them functional?

Click to expand...

Not 100% sure about that difference...but the 8gig showing under the pie chart would seem to indicate that the computer is only "seeing" 8 gig of ram (instead of 16gig).

Here's a link to how Apple suggests that the ram be installed in Mac Pro's:

Mac Pro: How to remove or install memory

...lots of install video's on You Tube as well...just make sure the videos are for 2008 Mac Pro's.

What I would do is...remove all eight ram DIMMS (marking those that were working previously)...and see if they look different in any way. Different manufacturer, different chip layout, etc. And put them together in 'Matching pairs"...then reinstall per the Apple instructions linked above.

If the ram DIMMS have little white labels on them (sometimes with spec. info on them)...check the ram speed if this info is there. You should be using "800 MHz DDR2 ECC fully-buffered DIMM (FB-DIMM) memory". If the speed on the ram is different than that...it might be the wrong ram. For example...667mhz or 1066mhz. Or if the ram is not "fully-buffered"...it might be the wrong ram.

Check everything out...and please report back with your findings.

- Nick

dobby said:

If you run the command I suggest among a lot of other info it also gives you info of the DIMM like :
Size :
Type
Speed
Status
Part number
Serial

Empty DIMM if there are any empty DIMM

Click to expand...

The process I followed is: About This Mac/More Info/Hardware/ Memory/Memory Slots
Here DIMM Riser B/DIMMs 1,2,3,4 are showing full and OK (Below identical mfgr and partts #s are showing for each). Interspersed are DIMM Riser A/DIMMs 1,2,3,4 are all showing empty.

If you're suggesting another path than this, please outline so I can follow. Other thread sent me to System Memory inside Applications Folder/Utilities Folder/ Activity Monitor,which is showing only 8GB

dobby said:

If you run the command I suggest among a lot of other info it also gives you info of the DIMM like :
Size :
Type
Speed
Status
Part number
Serial

Empty DIMM if there are any empty DIMM

Click to expand...

pigoo3 said:

Not 100% sure about that difference...but the 8gig showing under the pie chart would seem to indicate that the computer is only "seeing" 8 gig of ram (instead of 16gig).

Here's a link to how Apple suggests that the ram be installed in Mac Pro's:

Mac Pro: How to remove or install memory

...lots of install video's on You Tube as well...just make sure the videos are for 2008 Mac Pro's.

What I would do is...remove all eight ram DIMMS (marking those that were working previously)...and see if they look different in any way. Different manufacturer, different chip layout, etc. And put them together in 'Matching pairs"...then reinstall per the Apple instructions linked above.

If the ram DIMMS have little white labels on them (sometimes with spec. info on them)...check the ram speed if this info is there. You should be using "800 MHz DDR2 ECC fully-buffered DIMM (FB-DIMM) memory". If the speed on the ram is different than that...it might be the wrong ram. For example...667mhz or 1066mhz. Or if the ram is not "fully-buffered"...it might be the wrong ram.

Check everything out...and please report back with your findings.

- Nick

Click to expand...

Opened and checked all DIMMs. As I thought, they are identical; all info on tags is identical except serial #s. Appears to be OEM, as I was told. Also, they seem to work, as I switched the cards, and computer functioned the same. System profiler reported the same (Card A 1,2,3,4 all empty). Switched back.

Am late to a meeting; will check back later.

rexk said:

Opened and checked all DIMMs. As I thought, they are identical; all info on tags is identical except serial #s. Appears to be OEM, as I was told. Also, they seem to work, as I switched the cards, and computer functioned the same. System profiler reported the same (Card A 1,2,3,4 all empty). Switched back.

Am late to a meeting; will check back later.

Click to expand...

Ok...great work on your part. So I have two more suggestions:

1. Are the ram boards (the large card that is removable to install the ram DIMMS into) seated properly? I'm assuming that they are...since you have removed them a number of times already.

2. So you're saying that you switched the ram boards/cards around...by placing what was board A into the board B location...and vice versa? And the same location (board A) is reporting no ram?

This doesn't sound good, since it could mean that something on the logic board is bad (the slot that the ram board slides into). Maybe if you can...remove board A...and look into the slot on the logic board with a flashlight...and see if anything is plugging up the slot. Like dirt, fuzz, a small bit of paper...etc. Also take a look at the "pins" on the ram board...to see if they're messed up in any way.

If there isn't anything wrong that you can see...it might be a problem with the logic board (let's hope not)!

- Nick

Invest in a new Riser.


http://compare.ebay.com/like/130516319205?_lwgsi=y&ltyp=AllFixedPriceItemTypes&var=sbar

harryb2448 said:

Invest in a new Riser.

Click to expand...

That's what I was thinking as well Harry...might be a bad riser card.

- Nick

pigoo3 said:

That's what I was thinking as well Harry...might be a bad riser card.

- Nick

Click to expand...

If by riser card, you both mean the two cards that are each holding 4 2GB sticks of memory, then how could one of them be bad if, when I switch their positions from slot A to slot B and then back again, they each have a turn at showing up and functional (while in B), while the other shows empty while in A.? However, it is logical that the top (A) slot that the card slips into may be bad in some way, because that is what consistently shows empty in About This Mac.

I ran the hardware test again with the same result, except that under test results/memory, I noticed that at the top, it reports only 8GB memory, then proceeds to list 8 risers with 2 GB memory each, all showing functional. The logic board also passed the memory test, which reported no problems found at all.

I just figured out the Terminal system profiler command, which reports only 8GB RAM and under diagnostics states that Power On Self Test failed on memory for all four DIMMs in riser A. However, if I switch the cards, the one that failed here will show as good when in the B slot. The Diagnostics also reports that the Hardware Test passed.

rexk said:

If by riser card, you both mean the two cards that are each holding 4 2GB sticks of memory, then how could one of them be bad if, when I switch their positions from slot A to slot B and then back again, they each have a turn at showing up and functional (while in B), while the other shows empty while in A.?

Click to expand...

Yes...you're probably right. It just gets a little confusing keeping all the details straight...without seeing the computer in person.

rexk said:

However, it is logical that the top (A) slot that the card slips into may be bad in some way, because that is what consistently shows empty in About This Mac.

Click to expand...

This is what I was referring to earlier...that maybe the slot in position A is bad in some way, has a misaligned pin, or something is stuck in the slot (dirt, fuzz, hair, small piece of paper, etc.)...or there could be something wrong with that slot electronically...which could mean a replacement logic board (if you REALLY needed this fixed). Of course it would not be cheap!

- Nick