Not all Ram is created equal

[lesmac]

I just made a blue purchasing 2 x 8 gig sticks of registered RAM to augment my already installed 2 x 8 gigs of RAM.
I should have checked what type of RAM I had installed by opening the computer {Mac} first. I did reference the ram through the system report but that info is a bit limited. The already installed sticks were unregistered and they don't mix. The mac wouldn't boot.
So, if you see something like ECC-R, that's registered.
A trap for young players but I don't think I'm that young anymore just slightly dumb maybe.

[Len911]

There's a few other things like latency, voltage and firing order, usually it's easier to buy all new memory than trying to match the current memory, but with as much as you have, not practical, so something like this might be a safer bet:

http://www.crucial.com/usa/en/apple-memory

[lesmac]

Thanks Len.
I purchased through OWC and I might give them a call to see if they will accept a return and supply some unregistered RAM.
Fingers crossed.

[mojobone]

Shouldn't be a problem, I've had nothing but great experiences with OWC, and their rep's among the best in the industry.

[lesmac]

No Probs at all really though the first live chat Rep I spoke with before I installed the ram said it would be good to go but maybe we were having a parallel conversation and he thought I wanted to swap one for the other? Dunno
The next guy who helped me with the return authority was great. Very patient and thorough.
He supplied a link to some correct ram which I lost when live chat was finished. I found it by googling my existing ram. Funny thing is when Isearched the OWC/MacSales site for ram appropriate to my computer I got presented with the registered ram and no other options. I couldn't find what I wanted searching the site but I could by googling, go figure?

[mojobone]

I think you might wanna contact OWC with this info, just to spare a brother a similar fate. They seem like the type that would respond positively.

[andygabrys]

hey Les,

why don't you post your system specs so everyone can learn from your misfortunes.

I haven't ever had a problem with OWC ram but that is on the 2 mac Pros that I have owned. Perhaps its more complicated with iMacs / Macbook Pros etc.

[lesmac]

mojobone

I think you might wanna contact OWC with this info, just to spare a brother a similar fate. They seem like the type that would respond positively.

Yeah I will. I think they are a great company too.

hey Les,

why don't you post your system specs so everyone can learn from your misfortunes.

I haven't ever had a problem with OWC ram but that is on the 2 mac Pros that I have owned. Perhaps its more complicated with iMacs / Macbook Pros etc.

Model Name: Mac Pro [early 2009]
Model Identifier: MacPro4,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.66 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 8 MB
Memory: 16 GB
Processor Interconnect Speed: 4.8 GT/s

This is what you see in system report for ram in one of the four slots, a bit geeky:
Size: 8 GB
Type: DDR3 ECC
Speed: 1066 MHz
Status: OK
Manufacturer: 0x80CE
Part Number: 0x463732314755363546393333334700000000
Serial Number: 0x00000000

This model will take 48 gigs now according to OWC and I probably should have just loaded it up.

[This is in the computer with more of the same on the way]
16.0GB OWC Matched Set (2x 8GB) PC-8500 1066MHz DDR3 ECC SDRAM-
[This was the registered ram.]
8.0GB DDR3 ECC-R PC8500 1066MHz SDRAM PC3- [X 2]

Both types say matched.

This is the caveat for the registered ram which is on the page before adding the item to the shopping basket.
IMPORTANT OWC NOTE:
OWC p/n OWC1333D3MPE8GB (8GB modules) and OWC1333D3MPE16G (16GB modules) require that all installed modules be of the same p/n OWC 8GB and/or 16GB modules. Other existing Apple or 3rd party 1GB, 2GB and 4GB modules are not supported for use with these kits and need to be removed when these modules are added.

The alarm bells rang but I didn't understand the depth of it so after ordering and before installing I thought I'd better check with them online. I was given the go ahead but it was just one of those things. ..it happens sometimes. They accepted the return graciously but that was another 32 bucks I had to shell out. I should have known if my existing ram was registered or not, my bad.
The moral of the story is to keep a good record of your ram for future compatibility and probably don't buy registered if you don't want to be pigeonholed . The ECC-R is an identifier and I think there are others as well. Not having a choice of compatible ram when you go through the identifying process by computer model is a bit of a bummer too. Will see what they say about that...