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I want to put 2 more 1GB DIMM's into a server to bring its memory up to 4GB. But I'm wondering whether I can do this. The sticker on the memory currently in it shows PC2100 2.5v. It's an IBM eServer 345.

I'm just wondering if any PC2100 memory is compatible with it as the official memory is more than the server is worth.

Some memory for sale locally is Kingston DDR266 184 Pins PC2100 1G Desktop DIMM.

Would that work even though it's listed as desktop? Pin count is the same as the memory already installed.

Other option...:
2 x 1GB 2Rx8 PC2-5300F-555-11-80 RAM

This is PC2 but faster I guess. Would that operate in my server?

EDIT: Installed some PC2700 ECC Registered DDR memory CS2.5. Works perfectly!

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Thanks for all the answers. Important thing is the that it's 184pin ECC and CL2.5 (2.5V). indicates that I can use PC2700 and I have found a cheaper source for this memory. thanks again. – Matt Feb 21 '10 at 22:46
up vote 4 down vote accepted

Short answer: no. Those items you're describing aren't compatible to work with each other.

Your server takes ECC RAM. All your DIMMs must be ECC, as a requirement of the motherboard.

Check out the eServer xSeries 345 memory documentation at IBM's site.

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I almost always use generic Kingston RAM in all out-of-warranty servers and I've never had an issue to date, just as long as you do what David suggests and make sure you match everything.

CPU-Z will give you all the information you need to locate the exact kind of RAM you need. It's Windows only, but I'm sure there's an equivalent set of commands that will extract that info out of *nix machines.

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All it gives is the size, nothing else came up. – Matt Feb 21 '10 at 22:15
Did you check the "SPD" tab? It should give you a summary of each DIMM and which modes it supports – Mark Henderson Feb 22 '10 at 0:46
Yes, that showed almost nothing. It was behaving like it couldn't read the information so defaulted. – Matt Feb 22 '10 at 19:59
Very odd, I've never seen that happen before! – Mark Henderson Feb 22 '10 at 20:40

When I'm not sure what memory will work with a machine, I use the Memory advisor tool from crucial ( It will tell you exactally what specs you need for your box (and of course try to sell you their brand :).

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You should match the type, pin-out, voltage, and so forth.

Speed is generally less important - you can generally use faster modules in a board that officially expects slower.

PC2 will be DDR2, which will not work in your machine as it appears to want DDR (PC, not PC2).

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