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I have some Mac RAM at school that is not being used. It has never been opened before, and one of the PC's needs a little extra. Will putting Mac RAM in be an issue? The RAM also is not labelled, how can I tell the speeds of it?

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@David is right, there should be no reason for it not to work, at worst you'll need to check the memory types are the same (DDR, DDR2 or DDR3). Metal Gear Solid has a good image of how to identify the types here – Mokubai Jun 1 '11 at 19:35
is it possible to find out the Make/Model of the Mac it was going to go into, and the machine you are wanting to put it in to now? This may help us definitively tell you whether it will work... – Mokubai Jun 1 '11 at 21:42
It's not currently in a Mac. It's extra Mac RAM that was ordered to the school in maybe 2006. I don't have the specific RAM models for either, I'll have them by tomorrow though. – Simon Sheehan Jun 1 '11 at 22:21
up vote 5 down vote accepted

I don't see why it wouldn't work. IF the speeds (e.g. 1066, 1600, 800, etc) and the type of RAM (DDR1, DDR2, DDR3) is the same on both computers, it should work. It should say on the package of the RAM what the MHz (speed) or the RAM is and the type of RAM it is. If not, it should say on one side of the actual stick of RAM. It is very clearly printed on the stick of RAM, but if it is like in this case, and you have this RAM working in a computer, run CPU Z to figure out what type of RAM it is. Other than those way of identifying it, it will be weird...

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Thanks @Mokubai but too late... :( I found a nice high res picture on google though! :D – David Jun 1 '11 at 19:40
Yeah, ;) though without a sticker like that (as @SimonSheehan seems to suggest is missing in his question) identification could be, well, interesting... – Mokubai Jun 1 '11 at 19:44
Mis-matching speeds and typs of RAM should theoretically work and the computer would theoretically run... But your performance would be trunked down to the slowest of the chips. And it is a very bad idea to mis-match different RAM from different manuractures, or of different models, or of different size.… – CenterOrbit Jun 1 '11 at 19:49
Hmm... If you know which MAC it is supposed to go in, go to that computer, install CPUZ, it will tell you what type and speed of RAM it has installed. and there you go. Do you think that would be legitimate enough @Mokubai and @CenterOrbit? Also, as @CenterOrbit mentioned I would use only one manufacturer and speed of RAM... – David Jun 1 '11 at 20:39
CPU-z will tell @SimonSheehan the type of memory it needs to be to fit into the machine it is now going to, but personally I don't know enough about Macs to suggest a comparable tool to CPU-z to find out what type of memory that machine uses. – Mokubai Jun 1 '11 at 21:45

One big thing to note here is that modern Macs (with the exception of the Mac Pro) take SO-DIMM (laptop memory) rather than DIMM as you'll find in PCs (this is just a space-saving move on Apple's part). This means that the RAM is not usable in most desktop PCs, with very few exceptions. This is just because of a form-factor mismatch, it's the same technology but in a different physical package than desktop PC motherboards accept. It will be usable in most laptops.

Note that the Mac Pro takes RAM in a full-size DIMM package, but requires "fully buffered" FB-DIMMs. FB-DIMMs offer better memory density but require more expensive modules and controllers. So these RAM modules are only usable in other machines that expect FB-DIMMs, typically Xeon architecture servers.

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It's older Mac RAM, its been there for years. Its full size – Simon Sheehan Jun 1 '11 at 21:34
As long as it's a full DIMM package and not either registered (as in the older PowerMac line) or fully buffered (as in the Mac Pro line), it's the exact same product as used for desktop PCs. Just make sure you have the right generation (DDR/DDR2) and a speed that is greater than what is required by the motherboard (RAM speed needs to be greater than or equal to that expected by the motherboard, not just equal to). – jcrawfordor Jun 1 '11 at 21:36

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