Mac Pro 4.1 - 5.1 memory matching problem

[rueyloon]

Hello

hi, I just received 4 X 8GB from my ebay purchase (one of the 4 is dead, but that's another story)

I currently have
4 X 4gb and
4 X 1gb on my Mac Pro giving me 20gb in total

I can't seem to match the 8GB with any of my existing RAM, they are all 8500 ecc ram. I can't seem to find any info about ram not matching except the 16GB modules (info from OWC).

rgs
rueyloon

 

[h9826790]

Are they all UDIMM or RDIMM? You can't mix them together.

 

[rueyloon]

Are they all UDIMM or RDIMM? You can't mix them together.

Thanks I think you are right, the new RAM is stated at 8500R, my current ones is just plain 8500.

 

[stjames70]

Same problem

I bought certified mac ram from RAMJET to augment the six 8gb 1333MHz sticks I had on my 4,1. The two new sticks I got were placed on slots 4 and 8 -- they caused my Mac not to boot up and the front power white LED to blink quickly.

Called RAMJET and after verifying installed memory, I found out they sent me the supported unregistered DIMMs and I had registered DIMMs in my machine.

Ok. So they exchange the two 8 GB sticks with registered DIMMs.

You know what? Same problem. So I am thinking.....problem with slots 4 and 8?

So I swapped my existing slots 3 and 7 with the new memory to test the theory. And guess what? Blinking white LED of death on power button again!

Exchanged to original ram sticks, and voila, normal boot.

I think I may have to look carefully at the exact Hynix memory that is on that computer and try to obtain the exact same 8gb sticks.

Geez, I will tell you if that works. But I think that when you are upgrading memory, stick with the same vendor all the way through, whomever it is.

 

[rueyloon]

I manages to pair the 12gb that came from the nMP with the uRam in my oMP.

 

[666sheep]

I think I may have to look carefully at the exact Hynix memory that is on that computer and try to obtain the exact same 8gb sticks.

Geez, I will tell you if that works. But I think that when you are upgrading memory, stick with the same vendor all the way through, whomever it is.

That's perfect way, but not a must. Specs must match, that's basically all. Don't mix 2R with 4R, registered with unbuffered etc. Vendor and memory speed does not have to be the same.