How Much Memory Does Lightroom Need?

In Master Photography Roundtable by Jeff Harmon2 Comments

How Much Memory Does Lightroom Need?

I am trying to create a resource over at https://phototacopodcast.com that will help photographers answer all sorts of technical photography questions.  Especially questions about what computer they should buy to do post processing. I get constant questions from photographers about deal they see on computers and I know that the real reason they are asking me about this deal they have found is a serious hope that it will be enough to run Lightroom and Photoshop.  They are hoping that this computer that is in their budget is going to be good enough to do that well but they are nervous because they don’t really know what all the numbers and letters mean in descriptions of computers.

One of the questions photographers face when buying a new computer is if it is worth it to pay the extra money to upgrade the memory that will come in their new computer, or if the deal they are looking at has enough memory.  To help with this, I recently posted an article to https://phototacopodcast.com called How Much Memory Does Lightroom Need and I wanted to talk briefly about some research I did going into writing that article.

By the way, I did this testing on the most current version of Lightroom Classic 8.3.1 here in July 2019.  Previous versions of Lightroom and future versions may behave differently, so be sure you are subscribed (subscription is 100% free) to the Master Photography and Photo Taco podcasts to hear if this does change in the future.

Memory Is Different From Hard Drives / SSD Drives / External Drives

I have heard photographers confuse these two terms that describe computer components for many years now.  I get why it is confusing because we measure both components, memory and storage, in the same kind of numbers using megabytes and gigabytes.  Before we move on to how much memory Lightroom needs let’s see if we can make this clear.

When you talk about memory for a computer we are referring to the more technical term of Random Access Memory or RAM for short.  PC builders and enthusiasts will usually call it RAM instead of memory but Apple and most of the other big box sites that sell computers have taken to calling it memory.  The main processor in your computer (the central processing unit or CPU for short) that does the work for you computer doesn’t remember anything it does and so it talks to this memory at really high speeds and has it store the things that need to be remembered.

Memory can remember things when a processor doesn’t, but it can only remember things for as long as your computer is powered on.  As soon as your turn off your computer memory is erased. This is why we need more permanent storage to have the computer remember things even while it is powered off, and this is what hard drives, SSD drives, and external hard drives do for us.

Your computer will have far less memory than storage space.  Computers today come with memory measured in gigabytes (GB) with common sizes being 8GB, 16GB, 32GB, 64GB, and 128GB (some can go much higher but we’ll just kind of stop there).  Hard drives, the old magnetic spinning drives that have been around for ages, are mostly measured in terabytes (TB) these days, which is roughly 1,000 gigabytes. A 1TB drive is roughly 1,000GB, a 4TB drives roughly 4,000GB.  Hard drives can store far more information that memory and keep that information around for years even with no power.

Memory and hard drives then are a little easier to tell apart these days because memory is measured in GB and hard drives in TB.  But things get a little muddier when you talk about SSD drives. SSD drives are also capable of storing data for long periods of time without power (though this can actually be a problem losing information when they aren’t powered up for long periods of time compared to magnetic drives) but they are mostly measured in GB just like memory.  This is mainly because SSD drives or more expensive, but it does make it really confusing when you are looking at computer specs because you will have two things that have GB next to them.

Why Do Computers Need Memory?

If drives can hold more information and hang on to it for years without power, why do we need memory in our computers?  It has to do with the speed of drives compared with memory. Even though SSD drives are much faster than their slower older brothers the magnetic drives, they are not remotely close to the speed at which memory can read and write information.  Remember, that processor that is doing all the work in your computer can’t really remember anything, so it has to send messages off to something whenever something has to be remembered and it will have to wait until that happens. The slower that is, the more that processor has to wait before it can move on to doing more work – everything slows down.

What If You Run Out of Memory?

Every program you run on your computer needs memory.  Starting with your operating system (again, that is macOS or Windows) that will need some memory when you computer starts up.  Then every service and program you run takes memory. That DropBox client that is syncing stuff to the cloud for you uses some memory, even if it isn’t showing on your screen.  Your web browser is a very hunger application that needs a lot of memory, more and more with every tab you have open even if you aren’t actively browsing with it and it is behind other windows.

If we run out of memory the operating system, macOS or Windows, will resort to making “virtual” memory out of some space on your drive.  This is MUCH slower than memory as we have already discussed, so now that processor has to wait longer than it should before moving on to the next task and everything slows down.  

In some cases this substitute for real memory that macOS and Windows tries to do doesn’t work with some applications and you can get out of memory errors that makes what you are doing fail or even crash.  Both macOS and Windows have really come a long way in recent years to preventing actual crashes, but it can still happen today.

You need to have enough in your computer to run the programs you use and to have a little extra for the operating system and the little services we all end up having run in the background.  This is why it is important to understand how much memory Lightroom needs as you plan to buy a computer to do photo editing.

8GB Of Memory Isn’t Terrible For Lightroom!

I had it in my head just based on years of experience with Lightroom that it really needs more than 8GB of memory to work well.  I know that at times, when Lightroom was slow, I had checked and found it using more than 8GB of memory. Just here and there. I realized when I sat down to write this article that I hadn’t actually done all I could to test this.  I didn’t have actual data points of how much memory gets used as I use the various functions in Lightroom. I had a somewhat informed opinion of how much memory you should have in your computer to run Lightroom well but I knew I could do better.

I decided I had to run through a standard workflow in Lightroom and closely monitor how Lightroom used memory so that I could put that information in the article.  You can read the details about the testing I did over in the article, but I was really surprised to find out that basic workflows using import, Library, and Develop module functions actually didn’t use nearly as much memory as I thought they did.

Yeah, 8GB of memory is actually workable for Lightroom.  I can’t tell you how surprised I was to see this. Still, the news isn’t all good because there are definitely some features of Lightroom where you need more memory than 8GB, the article for that information.

16GB of Memory Is The Sweet Spot For Lightroom

If budget is so tight you can’t afford any more than 8GB of memory, you can make it work, especially if you shut down everything else that is running when you do your photo editing.  But let’s get real here, this isn’t how any of us work. The sweet spot in price to performance to provide you enough memory to do nearly everything in Lightroom and still have room to run web browsers and Photoshop at the same time is 16GB of memory.

There are even some use cases where photographers may need more than 16GB of memory, like 32GB or even in extreme cases 64GB.  Again, read the article for more information but having high megapixel (36+) and doing a lot of round tripping between Lightroom and Photoshop likely means you will need more than 16GB of memory.

By the way, Lightroom never seems to really release memory.  If you stop using it for a few hours it doesn’t go from using 7GB of memory back to what it took on startup (roughly 1.5).  This means a good strategy if things slow down would be to close Lightroom at which point it does finally release the memory and you can sort of start fresh.

The Lightroom Hardware Testing Project

Going through this testing of how much memory Lightroom needs made me realize that I needed to keep going down this rabbit hole.  I needed to dig deeper to get similar information about how much processor (CPU) and graphics (GPU) Lightroom needs to work well. Again, I have used Lightroom enough to have a rough idea of what it needs there, but I really wanted to know what features in Lightroom need more processor vs those that can use graphics processing.

What Makes Lightroom Feel Slow?

I spent some time searching around the Internet to see if others have done the hardware testing with Lightroom that I was looking for.  I found quite a few places where testing is being done on some of the features I don’t care as much about. They test import, export, convert to DNG, panorama merge, and HDR merge (like the excellent information over at pugetsystems.com).  

It’s not that I don’t use those features, of course I do.  Every photographer is going to use import and export for sure.  I just don’t really care if any of those take a little longer to happen.  I don’t really judge Lightroom as being slow based on the speed of those issues, although import is closest to something important to me.  I think that we all feel like Lightroom is slow based on how the Develop module functions.

When we move the sliders in the Develop module we expect to see the effects of that slider changing happen in real time so that we can decide when we should stop moving the slider and be done with that adjustment.  If we move the slider and we have to wait for even half a second for the change to be reflected on the screen, then Lightroom feels really slow. It is the features in the Develop module I am most interested in, and I haven’t seen the information about what hardware Lightroom needs for those sliders to work fast anywhere out there.

The “Lightroom Hardware Testing Project” Is Born

Finding literally no information out there about how much process, graphics, and memory each of the features in the Develop module need, an idea was born for some testing I could do to gather this information.  I also think I understand why this information isn’t really out there today – it is really hard to gather.

When you do hardware utilization testing you really want to build automated tests that can be run over and over so that you can compare apples to apples and maintain tight control over the variables you are changing between testing runs.  The features in the Develop module of Lightroom don’t really work well with existing testing tools. It is even hard to come up with a test that you can do manually so that you can try and do things the same as you repeat the tests after changing something.

After working on the problem for a little bit I came up with a way to test the Develop module features of Lightroom manually.  It means using those Develop module features in a way no photographer ever would but makes it possible for me to gather information about how computer hardware is being used.  The process is rocking every one of the sliders back and forth from extreme to extreme as fast as I can for one full minute, a horrible way to use the sliders in the Develop module that is entirely impractical but after giving this a try gives me the data I am looking for.  Once the minute is up, I let the computer recover for one full minute before moving on to the next test (this also gives me some time to note down what happened).

This will give me very quantifiable data points on what hardware the Develop module features need but it doesn’t really answer the question about how “fast” the feature is.  I can’t think of a good way to quantify that, so I am also recording with each one of these feature tests a very subjective “feel” of the feature. I use the feature as you normally would and then I record how that feature felt to me.  Was it as fast as other features? Was it slower? Did I have to really slow down on moving the slider or could it keep up with me as I moved it a reasonable but fairly fast speed?

I have decided on 51 Develop module features I can test this way.  After going through all 51 features tests, I will change one variable at a time to see what impact different hardware and configurations have. With there being 51 features to test and each feature test taking 2 minutes, it will be over 90 minutes just to do one set of tests. I plan to test PC vs. Mac, graphics processing and no graphics processing, previews and no previews, and 4K vs 2K. This is going to take a while.

In the end, I am hoping this Lightroom Hardware Testing Project (LHTP) will enable me to do two things:

  1. Do a much better job of helping photographers understand the decisions they have to make when buying a computer to run Lightroom
  2. Have some really good and detailed baseline tests to help me evaluate future releases of Lightroom and if Adobe has done a good job of improving performance.

If you are interested in helping out with LHTP, drop me a note by email phototacopodcast@gmail.com.

Doodads

Jeff: How Much Memory Does Lightroom Need article!

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Comments

  1. I really enjoyed this episode. I found it very helpful in understanding why my computer doesn’t run Lightroom very well. I look forward to hearing about the results from the future testing.

  2. Pingback: New Features of Lightroom Classic 8.4 - Does GPU Actually Work Now? - Master Photography Podcast

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