Bad RAM module replacement - compatibility concerns

L

Lothar

New Member
I have a brand-new high-end system (actually a server workstation) that has a bad memory module. The system has four 1GB DDR2 ECC DRAM 800MHz sticks (total 4GB).

I got the vendor to send me a replacement stick, but when I went to decipher the codes on the stick's label, I discovered that it seems to have two differences from the sticks that came with the system: (1) the CAS latency is 666 in the replacement, versus 555 in the original, and (2) the original sticks are labeled ECC, and the replacement is not.

I went to the replacement memory manufacturer's (Samsung) website, and looked up the specs on the part number for the replacement stick, and I see that it is fully-buffered memory, but I do not see anything in the specs about it being ECC.

My first question is, is all fully-buffered memory ECC, or should the stick's label specifically state "ECC" if it is?

Is there any compatibility/performance problem mixing ECC and non-ECC sticks on the same system?

Should I be concerned that the replacement sticks have a slower latency than the originals (willI notice any difference), and will they work okay together? Or should I insist that the computer vendor supply me with equivalent-spec sticks?

Here are the numbers off the original and replacement sticks:

Original stick (Nanya):
1GB 1Rx8 PC2-6400F-555-11-A2 . 800 . ECC
part # NT1GT72U89D0BD-AC

Replacement sticks (Samsung):
1GB 1Rx8 PC2-6400F-666-11-PO
part # M395T2863QZ4-CF76

Thanks,
Lothar
 
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It should say ECC if it has ECC. Usually registered memory is ECC but if it doesn't say it is ECC then it very likely is not. I'm pretty sure the RAM will work if you stick it in with what you already have (I would think the ECC RAM you have is buffered as well, if it's not then mixing them shouldn't work). Mixing ECC and nonECC makes all RAM effectively nonECC. The system probably shipped with ECC RAM for a reason though.

Also, mixing latencies shouldn't matter and it wont make that much of a difference.
 
Cromewell said:
It should say ECC if it has ECC. Usually registered memory is ECC but if it doesn't say it is ECC then it very likely is not. I'm pretty sure the RAM will work if you stick it in with what you already have (I would think the ECC RAM you have is buffered as well, if it's not then mixing them shouldn't work). Mixing ECC and nonECC makes all RAM effectively nonECC. The system probably shipped with ECC RAM for a reason though.

Also, mixing latencies shouldn't matter and it wont make that much of a difference.
Click to expand...

Thanks for the info, Cromewell.

It actually occurred to me to go into my system's BIOS after I posted my original message, and it does say there that each of the sticks (including the replacement that I just installed) is ECC. I don't understand why a memory manufacturer would ship ECC memory without making it clear, either on the module's label or the data sheet, that it is indeed ECC, as that would be a major selling point, wouldn't it? Could the BIOS be reporting incorrect information?
 
If it says that the stick supports ECC then it's safe to say it is, it's pretty unlikely that a release workstation BIOS has that kind of bug in it.
 
Cromewell said:
If it says that the stick supports ECC then it's safe to say it is, it's pretty unlikely that a release workstation BIOS has that kind of bug in it.
Click to expand...

Thanks very much, Cromewell, that answers my question. I have an unrelated question about this memory that I'll post in a new thread, if you wouldn't mind taking a look.
 
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