# How much RAM do you actually need?



## Graeme Brown (Apr 12, 2011)

Recently I've been using my 2010 MacBook Pro extensively with Lightroom, finding the performance ok-could-be-better, which got me thinking how to improve it. The laptop has the standard 4gb of RAM, so obviously one option is to increase that to 8 - but will it make a difference? 

Before everyone shouts "yes, you fool" ... I've installed iStat on the machine, which toolbar graphs for things like CPU and memory usage. What's clear from watching the info is that Lightroom rarely uses more than 1gb of RAM, and there is often 40-50% of total memory free. On that basis I'm wondering if adding more RAM would just give me more free memory, which isn't worth paying for, or if Lightroom would start using more memory because there is more available.


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## Mark Sirota (Apr 12, 2011)

What more memory would provide is a larger Unified Buffer Cache for the operating system, which could speed up some Lightroom operations.  Oversimplifying only slightly, the UBC is as big as it can be -- any time an application requests some memory, it gets stolen from the UBC.

The UBC is used to cache things like disk I/O.  So if you read a block of a file, then the next time you go to read that block it may be in the UBC and therefore be much faster than if the OS had to go back to the disk to get it.


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## edgley (Apr 12, 2011)

Do you have a 5200RPM internal drive?
If you do I would imagine that the benefit of upgrading that will matter more than going from 4 to 8GB


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## sizzlingbadger (Apr 12, 2011)

I have a MacBook Pro and recently upgraded from 4GB to 6GB and it didn't make much difference to running Lightroom. I only have a web browser and email open at the same time. LR didn't even seem to use much more of the memory and this probably because other factors were the bottleneck. I replaced the factory 5200rpm 250GB drive with a 7200rpm 750GB drive and that made a noticeable difference to Lightroom. I re-installed all my software from scratch when I changed the drive and it was much faster doing the installations.

In my case the 6GB upgrade was really not for Lightroom but for Virtual Box so I can run Linux VM's and Oracle.


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## Graeme Brown (Apr 13, 2011)

Mark - I'm seeing 1-1.5Gb of free memory even during exports, which would suggest that the OS has all the memory it needs. Or is the UBC limited to a certain proportion of free memory?

Simon - Planning to install a 7200rpm disc, with a second one connected through eSata (express card). Considered an SSD for the internal, but I'm not convinced it will bring much performance relative to the cost.

Nik - that pretty much confirms what I'm thinking. Clean installs are always good, until you remember how much work you've put into setting up all the little apps and settings and so on


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## Mark Sirota (Apr 13, 2011)

Graeme, the UBC is within that 1.5 GB that's marked "free".  It's really impossible to know how much it's helping; I don't know of a way to view the hit rate for the UBC.


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## Graeme Brown (Apr 13, 2011)

Thanks Mark, you've convinced me to pony up for the upgrade ... it's not exactly a lot of money but I'm Scottish so I like to make sure I'm spending my pennies wisely


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## renambot (Apr 13, 2011)

I have a macbookpro 2010 with 8GB and, for me, it really helps. I'm often at around 6GB used (just right now it's 5GB). It helps when you have LR open, CS5 for editing with some plugins, plenty of web pages, and maybe word/ppt/keynote, ...
So yes, go for it.


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## bucket (Apr 13, 2011)

I'm in the same boat, I was looking at upgrading the ram and probably will. But I was also looking into solid state HD, and found that Segate makes a hybrid drive. It's supposed to be 80% fast but I haven't finished my home work yet and don't know if it's Mac compatible. I found a 500GB for $99 on new egg some I'm looking in to them.


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## sizzlingbadger (Apr 13, 2011)

Although going from 4 to 6GB didn't make Lightroom much faster, it did allow for PS CS5 to run better at the same time.


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## LouieSherwin (Apr 13, 2011)

Crucial - 8GB for less than $100 US - That seems quite cheap although that it is a lot of pennies.  But aren't US pennies cheaper than Scottish pennies? 

For sure a faster hard drive will make a big difference also.

-louie


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## Denis de Gannes (Apr 13, 2011)

My system specs are in my profile and signature. Works fine for me.
OS is on the Seagate Solid State Hybrid drive 500GB along with the Lightroom Catalog and ACR Cache in their default location. My image files are on the 1 TB HDD.


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