Activity Monitor shows less RAM

[Chris T]

I have a Mac Pro 2,1 (late 2007) running OS 10.6.8. I recently upgraded my RAM

I Installed another 16GB of RAM on top of the 16 I already have. It was fully compatible, installed as advised by Apple).

When I turn on the computer, The System Profiler says that I have 28GB of RAM, and memory chips are detected as installed. I've been using the computer for a couple of days with this RAM and it seems stable: no Kernel Panics etc.

However, when I run Activity Monitor (since I do a lot of heavy-lifting with some 64-bit music software), it says under System Memory that I only have 12GB!

I guess it's an error in AM, however if it's detecting RAM getting filled, I'm worrying that this will affect my system and not actually utulizie my 28GB of RAM.

Can anyone tell me what's going on with Activity Monitor and how I can get it show my correct amount of RAM? I have 6x4GB chips and 2x2GB Chips. The 2x2GB chips are located in Riser A.

thanks!

 

[tamvly]

A screen snapshot of the Memory section of Hardware from About This Mac would be helpful.

 

[mrichmon]

...

I Installed another 16GB of RAM on top of the 16 I already have.

...

I have 6x4GB chips and 2x2GB Chips. The 2x2GB chips are located in Riser A.

I'm a little confused. You said that you had 16GB of RAM and that you installed another 16GB of RAM, so a total of 32GB. But later on, you only list 28GB of RAM DIMMs.

Also, in the Activity Monitor the total RAM size is shown below the pie graph without any word label. If you are looking at the correct value then you might be running into one of the known display bugs in Activity Monitor on 10.6. The correct RAM size is shown in the System Profiler Utility.

 

[Chris T]

Sorry - I indeed have 28GB (Since 6x4GB chips, 2x2GB - see attached).

Since my first post, I noticed ECC errors in the System Profiler. It was on 2 chips - a 4GB chip, and a 2GB chip. Both in Riser A. I called the company who sold me the RAM (who had already returned the new batch (16GB) of RAM due to Kernel Panics previously). They said I should systematically take out RAM until I narrow down which chips are giving me the ECC Errors.

I went through and tested each pair of chips (doing clean reboots every time). NONE gave me errors. I then had 28GB in System Profiler, with NO errors (and Activity Monitor was back to normal, showing 28GB).

HOWEVER, this morning it's now showing an ECC error on a chip in Riser B !! This is NOT the same chip as before (and on a different Riser).

While my system seems stable so far (no weird crashes), I am worried that this is the symptom of a bigger problem. Can anyone shed light on these ECC errors and whether it's something I should be concerned about?

In light of what you said about the Activity Monitor bug in OS 10.6, can I assume that these issues are unrelated?

Would sending the RAM back (even though there are no crashes etc) be a good idea, or am I just as likely to get ECC errors with the replacement RAM?...

Thanks!

 

[birdpathp]

i agree it,This is NOT the same chip as before (and on a different Riser).thanks

 

[mrichmon]

To track down your ECC errors you'll need to run some memory tests. The Apple Hardware Diagnostic tool on the install DVD has a memory test cycle.

Additionally, the software "Rember" http://www.kelleycomputing.net/rember/ is quite good.

But memory testing to find the bad DIMM is somewhat complicated. The test software can only test the memory cells not in use by the operating system and software that is running. So often you end up needing to perform multiple test runs to find the problem.

One easy protocol is to attach a small post-it note to each DIMM so that the memory modules are labeled:

• slot1: DIMM1
• slot2: DIMM2
• slot3: DIMM3
• slot4: DIMM4

Then perform an intensive (long) memory test. If no errors are reported then re-arrange your memory modules to:

• slot1: DIMM2
• slot2: DIMM1
• slot3: DIMM4
• slot4: DIMM3

or

• slot1: DIMM3
• slot2: DIMM4
• slot3: DIMM1
• slot4: DIMM2

Then re-run the memory tests.

The particular shuffling that can be done depends on how your system arranges the DIMM slots into banks. But the purpose is to ensure that the physical memory modules that previously were holding the operating system and software are moved so that they are free when the memory test runs. Conversely, it means that the physical modules that were previously free and passed the tests are now holding the operating system so that the untested modules can be tested.

You should expect that a memory test will take several hours to run.

 

[Chris T]

Thanks. I'll try that.

Here is the current situation on my System Profiler.

 

[Chris T]

Just looked at my System Profiler, and the ECC Error is now on an entierly different slot. The errors are constantly moving from one slot to another, with no apparent logic. Sometimes 1 or 2 errors. Sometimes none.

The conclusion I've come to is that this RAM, which is all from one company, despite being bought in 2 batches (a couple years apart), is randomly giving me ECC Errors. Therefore, due to the unpredictability of these errors, I have to conclude that ALL the chips are "bad" - or at least causing ECC Errors.

I don't assume this company will simply refund my money - just replace the chips. However they'll probably replace them with chips from the same or similar supplier, which implies I'll get similar ECC Errors in future.

Do you think it's worth replacing all this RAM (from the same company), or should I just live with it? So far, there is no noticeable problem on my system (kernel crashes etc), so it might be something I could live with, assuming nothing bad goes wrong in the future that's memory-related... I guess my biggest fear would be that this "bad" memory cause bigger problems (e.g. in Motherboard / hard Drive) which could be really bad...

Thoughts?...

 

[mrichmon]

Thoughts?...

Well, this can be a motherboard issue but those typically show up as one or more slots that are consistently bad. So, for now you can ignore this possibility.

From what I've followed it sounds like this problem has been observed after you purchased the new RAM. (Though possibly you were not testing RAM before the new RAM.)

If you had at least a few months of using the computer without problems before installing the new RAM then the RAM is immediately suspect. I would remove the two new sticks and re-run the tests. If the system is good without the new RAM installed then you've identified the source of the problem.

 

[Chris T]

I'm now getting EEC errors on all 8 chips, though with no apparent pattern or logic.

I'm pretty sure it's the RAM. Company has offererd to replace it for free, however I've a strong suspicion I'll just get more RAM with EEC errors (i.e. they'd use the same supplier(s).

Do you think it's worth replacing all this RAM (from the same company), or should I just live with it? So far, there is no noticeable problem on my system (kernel crashes etc), so it might be something I could live with, assuming nothing bad goes wrong in the future that's memory-related... I guess my biggest fear would be that this "bad" memory cause bigger problems (e.g. in Motherboard / hard Drive) which could be really bad...

Thoughts?...

 

[flowrider]

^^^^Sounds like you need to replace it. Make sure the new RAM is matched and all of the same speed. I've used my RAM supplier since 1986, and I've never got a bad stock or RAM in all that time. They are Mac Specialists and their RAM has a Lifetime Guarantee.

http://www.datamemorysystems.com

Lou