4GB RAM upgrade iMac 7.1 into a coma

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Level 1

8 points

4GB RAM upgrade iMac 7.1 into a coma

OK. Trying to upgrade my Dad's 20" iMac (v7.1 Intel Core 2 Duo 2.4GHz) from its base 2GB RAM to 4GB.

Followed instructions explicitly and installed a pair of compatible 2GB modules from Crucial. Switch Mac back on and fan whirls but screen doesn't appear and machine 'acts dead'. NOT grey screen of death - just nothing - blank screen.

So remove one of the modules and the machine works fine BUT ONLY WITH 3 GB RAM. Doesn't seem to matter which slot the 2GB module is in, a total of 4GB results in the machine not starting. I got a replacement pair of modules from Crucial, incase one of them was duff, but the problem persists.

I've seen this posted a couple of times in other fora, but no solutions posted.

Any suggestions?

Cheers

J

MacBook Pro 17", Mac OS X (10.6.3), iMac 20" (iMac 7.1 Intel Core 2 Duo 2.4GHz)

Posted on Apr 3, 2010 12:38 PM

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Answer 1

den.thed

Level 10

91,468 points

Apr 3, 2010 1:00 PM in response to drjbscott

Hi J

Welcome to Apple Discussions

Are they PC2-5300 667MHz modules?

The reason I ask is because a single PC2-6400 800MHz may work in that model mixed with a PC2-5300 667MHz module, but a pair of PC2-6400 800MHz modules will not.

If you ordered the correct specification modules and they are not working, then send them back and order from OWC.
http://eshop.macsales.com/item/Other%20World%20Computing/53IM2DDR4GBK/

Dennis

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Answer 2

drjbscott Author

Level 1

8 points

Apr 3, 2010 3:10 PM in response to den.thed

Interesting....

Reading the product code off the module the boards are listed as PC2-6400 - although System Profiler reads this as 2GB 667 MHz.

I'll try a pair of 5300s.

Cheers.

J

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Answer 3

den.thed

Level 10

91,468 points

Apr 3, 2010 3:22 PM in response to drjbscott

Yup, iMac are picky and that one takes PC2-5300.

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Answer 4

Virtuoid

Level 1

0 points

Apr 20, 2010 8:27 AM in response to den.thed

Hi i wish i Re-Open this topic cause i just bought from Crucial 2 sodimms rams to upgrade from 2 to 4 GB my imac

here them: 2gb 200pin DDR2 SODIMM PC2-6400 at 800hz when i attach em i have the same problem like above.

The same if i attach 1 ... here my imac specifics i must buy new ones PC2-5300?

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 2 GB
Bus Speed: 800 MHz

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Answer 5

babowa

Level 9

78,568 points

Apr 20, 2010 8:51 AM in response to Virtuoid

Well, it appears as though your Mac is the same model as the OP's - therefore, it would obviously require the same type of RAM.

If you would check the link provided by den.thed, you can specify your model and get the right RAM; I only buy my RAM there.

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Answer 6

Virtuoid

Level 1

0 points

Apr 20, 2010 12:52 PM in response to babowa

how if i have a 800mhz bus i can't apply 800mhz ram but just 667mhz?

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Answer 7

babowa

Level 9

78,568 points

Apr 20, 2010 2:22 PM in response to Virtuoid

Did you check den.thed's link or read his post at all? When you find your imac model in the list and click on more info, it'll plainly state:

+PC2-5300(667MHz) DDR2 memory+

The system is not necessarily the same as the RAM specifications. Before ordering memory, you should check your Mac's requirements/specs.

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Answer 8

Apr 20, 2010 2:32 PM in response to Virtuoid

The bus that it is referring to is (IIRC) be the CPU's bus of 800MHz, not the RAM bus. I had this same though as you originally when I attempted to put two 800MHz sticks in my MacBook. It didn't work out, but is running great with two 667MHz chips.

So 800MHz front-side bus for the CPU, 667MHz for RAM bus. Hope that clears it up a bit for you! :}

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Answer 9

den.thed

Level 10

91,468 points

Apr 20, 2010 6:08 PM in response to Virtuoid

As pointed out by others a Mid 2007 7,1 iMac uses PC2-5300 667MHz ram.

http://support.apple.com/kb/SP16

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