Can I use 2GB + 8GB Ram with different frequency?

Hi there,

I wanted to upgrade my MAC Book (mid 2010 - 7.1) with 2x4 GB Ram chips from Kingston. I got the latest El Capitan running and even with just 2x2GB it's running actually very good.

I bought two Kingston KVR16LS11/4 - with 1600MHz. The dealer told me that it will work with any MACBook.

So I installed the two chips and nothing happened after I press the start button. ?!?!

I soon found out, that the frequency is the problem. (Stupid me). So I just entered one 2GB(1066MHz) + one 4GB(1600MHz). The system starts and gives me 6GB at 1066Mhz. I was working a little with the computer and everything seems to be fine. The startup take some more time - but this could be something else as well.

The problem is - I am in Peru and it's a friends computer. Here it's almost impossible to get chips with 1066MHz (tried Mercado Libre - like the Amazon of South America) 1333MHz is possible - but no 1066Mhz available.

Soooo - The question ist now if I could use 2GB(1066) + 8GB(1600) or 8GB(1333)

Because it will be much easier to exchange the two 4GB with one 8GB with our dealer - then finding two 4GB(1066)... The Apple homepage tells me that a MAcBook Pro 7.1 can handle up to 16GB.. Should work - shouldn't it?

The best would be to get one 8GB chip from OMC - unfortunately I didn't know about this before... I asked OMC already and they said that the 2GB(1066) + 8GB(1066) setup will run.

Ok - who has experience on this or even running a system with unequal DDR3 chips at different frequency.

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Greetings

Update (08.06.2016)

Hi there,

I just wanted to tell you that I successfully installed a 8GB (1333Mhz) Ram in the MAC Book and it's running smooth and fast now. Yesterday I did some extensive testing with photo- and video editing software...

No Problems so far... LR5 runs as fast as on my MBRetina"2013"...

Thx

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Answered! View the answer I have this problem too

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Yes, both modules need to be the same clocking spec. you can't mix them. But, they can be different sizes (I do try to use matched pairs as you loose interleaving when they are different sizes). And, yes with the newest firmware on your system you can support one 8 GB module.

Here's the link to the Apple T/N to check the firmware: About EFI and SMC firmware updates for Intel-based Mac computers make sure your at this level or newer.

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ehm - you read about the fact that I mixed DDR3 with different frequencies. ?!?

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Yes, thats the issue. Not all modules play nice. What may appear to boot up won't be stable if the given module is on the edge. Sizes is a different issue than clock. You need to be at least at the expected clock speed of what the system states is needed. You can always put a faster one in. but one that is too slow for the given system may appear to work but later not be stable enough.

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As I mentioned before it is impossible to get 1066Mhz RAM in Peru. OMC is an option but since we already bought those 2 RAM we would like to get our money back or at least change it to on 8GB (1333 or 1600) one. Of course that's not perfect but the system should run with 10GB and maybe a little bit lower speed (not frequency) since it's an unmatched pair. In case we get a refund I will buy a matched 4GB+4GB from OMC.... But spending double money is a NO GO for us.

I am getting confused by the answers. "I can but always a faster one in" - > does it mean I can get a 1600Mhz 8GB now OR a 1333MHz 8GB.

The 1333 has the same 1.5 Voltage - 1600 running at 1.35V

Since the 4GB(1600) Mhz seems to work I am still tending to get this frequency...

Greetings

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Let me try to straighten out the issues:

- Can't use a module who's clock is less than what the system is spec'ed to. But! You can use faster modules. Older slower modules are getting hard to find so you'll likely will only find the newer faster modules.

- Both modules really need to be the same clock spec. You can encounter stability issues when you stress the system. I've found the really older modules don't play nice with the newest generation of modules. Look at the chip size: The bigger chipped and the ones with more chips are the older (compared to the same sized module). This is more so when you have the same sized modules Vs different sized modules (1GB Vs 2GB etc...).

- You can't mix the newer low voltage modules with the older modules. Low voltage modules in laptops offer longer run time on battery.

- Matched pairs (same manufacture & version) allow you to leverage interleaving which spreads the load across the modules so the access is quicker.

Here are one other point that doesn't apply here but is good to know if you work on iMac's:

- A Bank of modules needs to be the same size & clock

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Hi Martin,

I haven't mixed RAM modules of different speeds for quite a while now, but haven't had any problems with it in the past. As you demonstrated with the 2+4 combo, it will switch back to the lower speed that the MacBook can actually handle.

2+8 shouldn't be a problem either.

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Hey - Should I get 1333MHz or 1600MHz -> in case we don't get a refund for the two 4GB sticks...

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You should use the 1333Mhz one but either way your gonna end up with 1066.

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Hi there,

I just wanted to tell you that I successfully installed a 8GB (1333Mhz) Ram in the MAC Book and it's running smooth and fast now. Yesterday I did some extensive testing with photo- and video editing software...

No Problems so far... LR5 runs as fast as on my MBRetina"2013"...

Thx

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Hi there,

I just wanted to tell you that I successfully installed a 8GB (1333Mhz) Ram in the MAC Book and it's running smooth and fast now. Yesterday I did some extensive testing with photo- and video editing software...

No Problems so far... LR5 runs as fast as on my MBRetina"2013"...

Thx

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Martin will be eternally grateful.
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