[EDIT - made it clear Dell specifies "Both ECC and Non-ECC")

I bought some used RAM for my Dell Precision WorkStation T3500, but at power up I get an error beep sequence which the manual says means "1st 64 K RAM test in progress or failure".

Can some knowledgeable person look at the following details and tell me whether I've got it wrong?

Either that or the RAM is defective (they said pulled from a working server, but 🤷‍♂️). But there are 6 sticks and I've tried a couple of different pairs.

Dell's site says "The Precision T3500 uses 1066 MHz and 1333Mhz DDR3 unbuffered SDRAM memory...Both ECC and Non-ECC".

The seller described the ram as "Hynix RDIMM 4GB, DDR3 1333MHz, ECC, Registered". The text on it says "4GB 2x4 PC3 - 10600R - 9 - 10 - E1 HMT151R7BFR4C- H9 DB AA - C 0947". There are 6.

The machine has 6 slots that can take up to 4GB each. It currently has 2 x 4GB 1600 MHz. Here's what I tried:

  • filling the spare slots with the new ram
  • pulling the working ram and filling just those same two slots with the new ram
  • same again but with a different pair

Same results each time. I've now booted back up with the original ram.

Is there some other spec I should have considered? Is the problem "unbuffered" (Dell specs) vs "registered"? Must say I'm a bit lost.

  • According to the table in the link you posted, you need to fill the first 3 slots (12Gb) or all 6 slots (24Gb)...
    – DavidPostill
    Commented Jun 20 at 8:01
  • @DavidPostill Yes, I see what you mean. I'll remember that when installing the unbuffered RAM that I actually need :-) Interesting that it's currently running with 2 x 4GB (not set up by me).
    – Adrian
    Commented Jun 20 at 22:08

1 Answer 1


Yes, you bought the wrong RAM. Your workstation takes non-ECC, unbuffered DDR3. You bought ECC, buffered DDR3 RAM.

ECC means it is error correcting RAM, buffered means it has a fancy extra chip. Your workstation expects neither of them. You need normal, non-ECC RAM (which is always unbuffered).

Edit (Original question was edited)

ECC RAM comes in 2 flavours. One is buffered, one is unbuffered. Another name for buffered is registered. This is often shortened to RDIMM. Buffered RAM requires specific motherboard support.

Non ECC RAM only comes in unbuffered flavour.

You need unbuffered DDR3 RAM. Wether or not you want error correction on it is your choice. Its mainly a price difference thing.

  • Thanks for the answer. Just to be clear - Dell's spec page does say it will take ECC or non-ECC. But it also specifies unbuffered; is the fact that the ram is buffered sufficient on its own to prevent it working?
    – Adrian
    Commented Jun 20 at 9:06
  • @Adrian - That isn’t what your question says it supports
    – Ramhound
    Commented Jun 20 at 9:21
  • @Ramhound I've edited the question to include that Dell says it supports both ECC and non-ECC, which I'd missed out. It did say so in the page I linked to, but I can't expect people to follow that. Not my area of expertise, as I say.
    – Adrian
    Commented Jun 20 at 9:31
  • At this point I think I'm looking for confirmation that the problem is that you can't use buffered ram when unbuffered is called for.
    – Adrian
    Commented Jun 20 at 9:32
  • @Adrian - There is a difference between buffered (registered) and unbuffered memory. Just replace ECC with registered and this answer is still applicable answer is applicable anyways since the memory isn’t compatible with your system
    – Ramhound
    Commented Jun 20 at 9:43

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .