Is this memory stick compatible?

The other day a 256MB memory stick failed in my computer and I had to replace it with a 128MB stick that I had as a spare.  That left me with 256MB total (two 128MB sticks installed).   I decided it was time to buy two new 256MB sticks and upgrade the system to a full 512MB.

The system is a Dell Dimension L733r.

The memory stick that failed said, "PC100 256MB" on it.   I went onto EBay and found the following ad #: 110308864535    It was advertising, "2 X 256mb - 2 Sticks - PC100 RAM MEMORY 168 pin ECC".   I thought that would be a compatible replacement so I bought it.

When the new memory arrived, I plugged it in and a lot of beeping ensured that basically means, "This memory doesn't work in this system!"

The new memory (made by SimpleTech) says the following on it:  "256MB SYNC 100Mhz, CL3 ECC".   I am suspicious because it does not say PC100 on it and I'm wondering if I bought one thing but actually received another.  

If I can get confirmation that what I received is not what I bought, then I can ask the vendor to put things right.   But, of course, there's a possibility that I've simply bought the wrong memory and the problem is mine.   Can someone help me resolve this?

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The memory you bought seems to be ECC memory which means it is error correcting and more expensive.  I doubt your Dell Dimension requires ECC memory.
Your computer does not support ECC memory. That is more likely your issue.

Try this link

If the doesn't work, go to and search for dell dimension l series and you will see some FAQ there
gallymonAuthor Commented:
So, are you saying that the fact that one says PC100 and the other says 100Mhz is not relevant where as the fact that the new memory is ECC may make it incompatible with my system?
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The PC100 means that the RAM speed is 100Mhz. Which is what you got. Your computer just does not support ECC RAM. That is from the FAQ at crucial.
Yes, ECC cannot be used on a mobo which doesn't support ECC and vice versa...

Some ECC mobos can be toggled to not use ECC memory though.

Go here

and search for compatible memory by your computer model.   Then you can order from them or go someplace else to get new memory.

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