Strange memory problem - Macbook Pro 13

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Strange memory problem - Macbook Pro 13

Hello, I have two macbook Pro 13's, a 2010 and 2012 models. The 2010 had 4GB (2x2GB) of RAM and the 2012 had 8GB (2x4GB).

I replaced the 8GB with 16GB in the 2012 model with no problem.

When I installed the 2x4GB RAM modules into the 2010 Macbook, it would not boot and just beeped. I know this indicates a RAM issue.

I tried swapping the RAM position, still no go.

I tried just each of the modules one at a time in each RAM slot, still no go.

I put one of the old 2GB modules in the bottom slot and a 4GB module in the upper slot, and this works (gives me 6GB). Either 2GB module with either 4GB module works with this configuration.

Tried either of the 4GB modules in the lower slot with either of the 2GB modules in the upper slot, but no go either.

This would seem to indicate that there is a problem with the lower RAM slot, but why do the 2GB modules work there and the 4GB don't. Also, why wouldn't the system boot with just a 4GB module in the upper RAM slot.

It doesn't make any sense and I am at a loss to explain or figure out how to get 8GB usable in this 2010 Macbook.

Any ideas?

Thanks,

PEter

Posted on Apr 20, 2018 5:14 PM

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Answer 1

Best reply

stedman1

Community+ 2024

Level 10

256,398 points

Apr 21, 2018 8:30 AM in response to Peter Pappas

You're welcome.

Some models may be able to down-clock the RAM frequency to match the required spec, but for the most part in Macs, you will need to use correct spec. It seems to be common that if one stick of correct spec RAM is installed, you can get away with using an out of spec RAM. As to how stable that arrangement would be in the long run is debatable.

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Answer 2

Peter Pappas Author

Level 1

23 points

Apr 20, 2018 6:08 PM in response to stedman1

Thanks, I was always under the assumption that newer faster RAM would still work. They are both DDR3, the 2010 uses 1066MHz DDR3 and the 2012 uses 1600MHz DDR3.

Why does one stick work in the upper slot?

Thanks,

Peter

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Answer 3

Apr 21, 2018 8:30 AM in response to stedman1

As to how stable that arrangement would be in the long run is debatable.

Not debatable. This forum is littered with posts from users who tried using faster spec RAM, only to find it makes their MacBook Pro flaky -- it crashes maybe twice a day. Just enough to be a miserable pain, but not enough to figure out exactly what is wrong.

Lots of MacBooks CAN freely use mismatched sizes (I ran a 2 and an 8 in mine for a long time). The speed difference is undetectable, and the reliability is on target.

But stick with the specified speeds, not faster. Faster do NOT work properly.

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Answer 4

Apr 20, 2018 5:16 PM in response to Peter Pappas

The RAM is the incorrect spec for the 2010 model.

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Answer 5

Peter Pappas Author

Level 1

23 points

Apr 21, 2018 8:34 AM in response to Grant Bennet-Alder

Thanks, I guess I will spring for some PC3-8500 RAM.

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Strange memory problem - Macbook Pro 13

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