Can i use 800 mhz memory instead of 667?

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Can i use 800 mhz memory instead of 667?

I have a 24" 2.4 Intel Core 2 Duo iMac with 2 GB 667 MHz DDR2 SDRAM, I ordered 800 mhz memory by mistake. Is it ok to use the faster mem with the machine? Can it cause any problems?
Thanks for any help.

Mac OS X (10.5.5)

Posted on Nov 16, 2008 9:10 AM

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Answer 1

Nov 16, 2008 9:54 AM in response to ngav

So long as you purchased PC2-6400 DDR2-800 DIMMs in an appropriate capacity, you can safely use them in place of the PC2-5300 DDR2-667 units specified for use with your particular machine.

The inverse is not true: you could not use slower memory modules in a later, faster machine.

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Answer 2

den.thed

Level 10

91,546 points

Nov 16, 2008 10:19 AM in response to ngav

Hi ngav

Caution: many user's could not even boot there earlier 667MHz systems after installing the 800MHz ram, below are just a couple of examples.

http://discussions.apple.com/thread.jspa?messageID=8425089&#8425089

http://discussions.apple.com/thread.jspa?messageID=8230847&#8230847

Stick to the Spec's, the iMac's logic board will only allow you to run the ram at 667MHz anyway.

Dennis

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Answer 3

pogster

Level 5

5,123 points

Nov 16, 2008 11:52 AM in response to ngav

I have to concur with Dennis. There have been several posts where the wrong ram has caused problems. It's better to install the correct one.

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Answer 4

ngav Author

Level 1

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Nov 21, 2008 11:44 AM in response to ngav

Thanks for the replies. I returned the memory. It seem the computer would not boot. Oh well. Re ordered the correct ones. Thanks all.

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Answer 5

den.thed

Level 10

91,546 points

Nov 21, 2008 4:17 PM in response to ngav

Your welcome!

Thanks for posting the info, it help's us to confirm that PC-6400 800MHz ram should only be purchased for the Early 2008 Intel iMac's.

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Answer 6

boyboy

Level 1

9 points

Nov 25, 2008 8:39 AM in response to ngav

Having purchased iMac 20" 2 core Duo 2.16Ghz in June 2007 with 2GB memory already fitted.
Would like to know if this can be increased, and fitted by me, without involving a computer engineer?

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Answer 7

den.thed

Level 10

91,546 points

Nov 25, 2008 5:06 PM in response to boyboy

Hi boyboy

To get better assistance you need to post your question as a new topic instead of to an old answered thread.

The late 2006 2.16MHz Core 2 Duo's can be fitted with 4GB of matched ram, but it will only access 3GB.

http://support.apple.com/kb/SP28

The ram installation instructions below are also in your User's Guide!

http://support.apple.com/kb/HT1432?viewlocale=en_US

Dennis

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