Recommended Memory Size for Photoshop
Perhaps the most important aspect when it comes to memory for Photoshop CS6 is that you simply have enough in the first place. If Photoshop needs to use more RAM than there is available, you may suffer a huge performance hit and possibly even errors that stop your work completely. While the exact amount of RAM you will need depends on the images you are working with, we can provide you with an estimation to at least get you started.
To see how much RAM Photoshop CS6 uses for different sizes of images, we took our original benchmark image and simply resized it to 250MB, 500MB, 750MB and 1024MB. Then, while logging the total amount of RAM being used by the system, we ran the same benchmark series with four passes that we used in our previous testing. By installing 32GB of RAM in the system (which is more than Photoshop needed for even the 1024MB image), we can ensure that Photoshop has all the RAM it could possibly want.
Note that the data in the chart below has been compressed so that the benchmark loops for each image size are scaled to line up with one another. The larger images took much, much longer to benchmark, but scaling the results makes it much easier to compare the RAM usage between the different image sizes.
By default, Photoshop CS6 wants to allocate 60% of the system's RAM for itself. By taking the peak value and using this default allocation of 60% of the system's RAM, we can come up with the following recommended amount of RAM for each image size:
|Peak Usage||Minimum RAM||Recommended RAM|
|109MB Image||4778 MB||6689 MB||8GB|
|250MB Image||7836 MB||10970 MB||16GB|
|500MB Image||12304 MB||17225 MB||16GB|
|750MB Image||17589 MB||24624 MB||24GB|
|1024MB Image||22480 MB||31472 MB||32GB|
Keep in mind that this is for a single image with the default settings. While you will not run into too many performance issues if you are a bit under these amounts, if you get too far below you will likely see a huge drop in performance as Photoshop will have to write to the hard drive rather than the RAM. If you expect to have multiple images open, you will likely want to have a more RAM than our recommended amounts.
If more RAM is not an option, you can adjust the default settings a bit to make more efficient use of the RAM you already have. The easiest setting to change would be to turn up the allocated RAM amount above the default of 60%. However, if you do this you need to make sure you leave enough RAM free for the OS and other running programs or you will run into a multitude of other problems. If you want to see what else you can tweak in Photoshop CS6 to maximize performance, we recommend reading Adobe's How to Tune Photoshop CS6 for Peak Performance blog post.
While the speed and configuration of a computer's memory does make a small impact on Photoshop CS6 performance, there are likely many more important factors to consider before worrying about memory. The only time we saw a noticeable change in performance was when we used 1333MHz RAM and even then the difference between it and 1600MHz RAM was just over 1%. On top of that, we only observed this performance difference in GPU accelerated effects, which are only a fraction of the effects available in Photoshop.
Our testing shows that while the physical size of the RAM has no measurable impact on performance, using more memory channels did provide a very small performance boost. However, even that performance gain was under 1%, which is arguably small enough to be considered within a margin of error. It may seem like a waste to write a four page article just to say that it doesn't matter, but knowing for a fact that you do not have to worry about the speed of a system's RAM is very beneficial when configuring a system for Photoshop CS6.
From our results, we can conclude that for Photoshop CS6 the only major factor you should worry about in regards to memory is simply having enough RAM. This is going to vary from user to user, so it is important to have a good idea of how the system will be used and what sizes of images you will be working with before you decide on how much RAM you need. Most users will only need 8-16GB, but professionals who work with very large images may need 32GB or more to satisfy their needs. As for the speed of the RAM, we would suggest simply matching whatever speed your CPU natively supports (most likely 1600MHz). Faster RAM might give you a very slight performance increase, but in our opinion is not worth the additional risk of failure.
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