# Can LR 6 Benefit from 32 GB of Memory?



## HamsterDR (May 31, 2015)

I have a (late 2014) iMac 27 Retina with 16 GB of RAM.  I can upgrade to 32 GB for about $100 and I am considering this because of another software product I am using.  Can LR 6 on OS X actually benefit from the increased memory?  The system requirements only say 8 GB of RAM is recommended - and I have that covered.  I can watch the Activity Monitor memory tab, and LR doesn't seem to ever use more than 2 GB.  (I generally don't run multiple programs at the same time - LR generally runs by itself.)

David


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## mcasan (May 31, 2015)

If I had an Retina iMac I planned to keep for a few years and could upgrade from 16GB to 32GB for $100 I would be on that like white on rice.  You can not predict exactly how the OS and every app you might run in the future will benefit.  One thing is for sure.....they will not suffer as a result of the memory expansion.


"Moderation is a fatal thing. Nothing succeds like excess."     Oscar Wilde


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## Woodbutcher (Jun 1, 2015)

Take a look at what the Activity Monitor says you are using with Lightroom open.  On my imac (non-retina), I was using all 8GB when Lightroom 5.7 was open.  Added 16GB and am only using a little more.  So with Photoshop and Lightroom up, I'm still in the 10GB or so use area.  I suspect you might use more with a Retina display, but I suspect you won't need 32GB.  On the other hand, it is cheap so adding it won't break the bank.  And likely won't hurt performance.


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## HamsterDR (Jun 2, 2015)

I have checked Activity Monitor, and the highest memory usage for LR 6 that I have seen (so far) was a little less than 4 GB.  Maybe it would use more when importing a large volume of new photos and building previews - as I know that is multi-threaded now.  I did decide to buy more memory, because I have another (statistical analysis) program that can use the additional memory.  LR 6 runs decently on my MBA with only 4 GB of memory, so I doubt if this is an issue for LR.  Given the larger memory size generally available these days, it would be nice if LR did more in RAM - avoiding disk I/O helps performance a lot.  (I have the 1TB hybrid drive - but I doubt if the system swaps any of the LR items into the SSD.)

I appreciate the comments.

David


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## Jim Wilde (Jun 3, 2015)

Lightroom does use the system cache quite extensively, so while the application itself may not appear to use a lot of memory (though I've seen it use around 8gb when doing a photo-merge), it could still benefit from larger amounts of system memory, particularly in the Library.


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## HamsterDR (Jun 3, 2015)

LR6 does take advantage of the extra memory.  I added the new memory and now have 32GB of RAM in my iMac.  I had some batches of JPGs to import.  During the import process - and the generation of previews - LR uses more and more memory.  Interestingly, once the import is done, it doesn't release the memory.  On the next import, it grabs _more_ memory.  By the time I had finished importing nine batches of 40 photos each, LR 6 was using 26 GB of memory (per the activity monitor)!  I could just watch it growing and growing.  Nothing else was running, and with 32 GB of hardware RAM, no memory was compressed and swap was 0.  Going into develop and viewing one of the imported photos didn't release any memory.  Exiting LR6 did release all the memory.  My guess is that since the memory was available, LR 6 wasn't bothering doing any memory management.  If I had another large process asking for memory, then I expect LR 6 would release some memory, but I haven't tested that.  Very interesting - I assume this is intended behavior and not a bug.  I have never looked at memory usage for LR before.

David


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## Linwood Ferguson (Jun 4, 2015)

I don't think you will see a difference in 16 and 32 but I'd certainly get the 32 for $100 anyway if it's the same speed memory. 

Check that they aren't selling you a downgraded speed.   

PS. I don't do Mac's so take all this with a suitable grain of salt.


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## tspear (Jun 4, 2015)

The few upgrades I have seen like that generally involve slower memory.
So check the memory read / write speed plus the bus throughput.

Tim


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## HamsterDR (Jun 4, 2015)

The memory I installed is from Crucial and is designed for the iMac 27 Retina.  The specs for the new memory matches the existing memory exactly - in fact, the memory chip manufacturer for both the original and new memory is Micron.  I am quite sure there is nothing wrong with the new memory (it passed several extensive hardware tests).  Performance on import seems a bit faster than normal, but I was importing JPGs and not RAW images.

I wonder if this is in fact a memory leak for LR - I never saw this behavior when I had the original 16GB installed.  I am going to try running with some other memory intensive applications and make sure LR releases memory when it needs to.

David


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