In prepping this series of articles, we read much of the information already published elsewhere. Some of the suggestions work. Others are complete myths. Some of the advice (including in our old blog post!) is simply outdated. Some suggestions can even make Lightroom slower. So let’s debunk some myths! These are the main ones to avoid…
Myth #1: GPU – Everyone should turn it off (or on)
We’ve seen many posts saying that the Use Graphics Processor pop-up in Preferences > Performance should be turned off. We see almost as many saying it should be turned on. The recommendations have changed significantly over the years, as the GPU has been used for more and more performance improvements.
Auto is now the default, and it’s the best choice for most people. It only enables GPU performance enhancements that are expected to work well, and leaves potentially buggy options disabled.
However, there are many possible combinations of GPUs, drivers and driver settings, especially on Windows. A bad combination can cause slower performance, strange artifacts on the screen, or even crash the entire system.
To give you additional control, there are two Custom settings. These allow you to experiment with what works best on your system. (Note: these may not be available depending on your GPU.)
- Use GPU for display visualization is the same as the Enable Graphics Processor checkbox in earlier Lightroom versions. It uses the GPU to accelerate the drawing of pixels on the screen.
- Use GPU for image processing uses the GPU to speed up image calculations in the Develop module, so when you move a slider, the preview is much faster to update, and can improve Library preview performance too. This does require a more powerful graphics card than the display visualization option, but also has greater performance benefits.
You might select Off if your graphics card is underpowered, or continues to have issues such as performance degradation, crashes or artifacts after you’ve updated the driver.
There’s additional information on Adobe’s Support pages.
Myth #2: Render 1:1 previews to speed up Develop
We saw loads of recommendations to render 1:1 previews in order to speed up loading in the Develop module… however pre-rendered 1:1 previews aren’t used AT ALL in the Develop module. There are some good reasons to render 1:1 previews, such as quickly zooming in the Library module, but they won’t help in the Develop module.
We’ll come back to where different types of previews are used in a future post, but if you’re wondering about the complete preview loading logic, there’s a flow chart diagram on pages 503 & 506 of our Lightroom Classic – The Missing FAQ book.
Myth #3: Make the Camera Raw Cache huge
In Victoria’s 2009 blog post, she recommended enlarging the Camera Raw (ACR) Cache size in Preferences > File Handling to 50GB saying, “Bigger is better!” However, from Lightroom 3.6 on, the cache format was changed and compression applied. This meant the cached files now take up a few hundred KB each, instead of multiple MB. This means you can now fit a lot more cached images into the same amount of space. (If you want to understand the Camera Raw Cache, including ways to preload it, see pages 501 & 507 of our Lightroom Classic – The Missing FAQ book)
We still see lots of posts saying to enlarge your cache size to 75GB, or even as much as 200GB. For most people, it IS worth enlarging the cache from its 5GB default. The number of photos 5GB will hold depends on your preview size. For example, 1440px will cache approx. 11,100; if you use a preview size of 2880px, then 5Gb will hold 2,275. So, 75-200GB is overkill for most people. You’d be better off with a 5GB-10GB cache on a fast drive (e.g. SSD) than a much larger cache on a slower drive.
But there’s one more thing. If you’re slowly stepping through the photos consecutively in the Develop module, the full resolution data is preloaded in advance, negating the need for the Camera Raw cache. So it’s only really helpful if you’re skipping around in Lightroom, or you don’t have enough RAM to hold full resolution cached data.
Confused about all these previews and caches? Don’t worry, we’ll come back to them in more detail in the Previews & Caches post, including an even better trick using Smart Previews instead of the Camera Raw cache.
Myth #4: Use loads of little catalogs
Another frequent “solution” for performance problems is breaking the library up into multiple small catalogs. To be fair, a few things are slightly slower on a big catalog. Most notably, opening the catalog and backing it up. Also, updating smart collection counts can slow things down on big catalogs (although there’s a solution for that in a later post). But let’s just define big catalogs: 1 million photos is a big catalog, 50,000 photos is a small catalog.
These slight delays in opening and backing up are easily offset by the lack of hassle trying to search and maintain multiple catalogs, and the confusion that can result.
If you’re a high volume working photographer, there are some arguments for multiple catalogs. If you’re shooting thousands of photos a week, then a catalog per year or a working and archive catalog can be a good compromise. Or if you can’t risk the Jones wedding party seeing the photos from the Smith baby session, perhaps one catalog per job. BUT for the majority of photographers, multiple catalogs create far more problems than they solve. Just optimize the catalog regularly, and keep it on a fast drive.
Myth #5: Delete all of your previews
The final suggestion we frequently see is to empty Lightroom’s caches and delete previews regularly. But stop and think about that suggestion a moment. Lightroom has to display previews, otherwise you’re looking at a blank screen. So which is quicker? Loading a small JPEG preview file from the hard drive, or loading a full size raw file and applying complex calculations to it? If you’re unsure of the answer, trust us, loading a small JPEG preview is much faster! So why would you want to throw away all of the previews you’ve already rendered, and force Lightroom to do all these complex calculations again?
There are some circumstances in which you might need to delete previews. If the previews are corrupted (shown by an error message or lines/dots/strange colored areas appearing on the photos, or the wrong preview being displayed), then you’ll want to trash the preview cache. Or if you’re desperately low on hard drive space and can’t remove any other files, then you may want to trash the preview cache.
If you do delete your previews, remember that Lightroom will have to build the previews all over again the next time you try to view them, which will make Lightroom slower. To save staring at a loading overlay, you can re-render the previews overnight by selecting the photos and going to Library menu > Previews > Build Standard Sized Previews.
That’s the main Lightroom Performance myths, so next week, let’s talk about hardware.
For extensive information on Lightroom Classic, see Adobe Lightroom Classic – The Missing FAQ.
If you have the Photography Plan, then as well as Classic you have access to the Lightroom cloud ecosystem including the mobile apps and web interface. For more information on these apps, see Adobe Lightroom – Edit on the Go.
Note: purchase of these books includes the first year’s Classic or cloud-based Premium Membership (depending on the book purchased), giving access to download the latest eBook (each time Adobe updates the software), email assistance for the applicable Lightroom version if you hit a problem, and other bonuses.
We also have a special bundle offer for the two books. This includes Premium Membership for the first year as described above for the whole Lightroom family!
Originally posted 29 August 2016, updated May 2021.