We all know photos can take up a lot of space on your iPhone or Mac. And because most videos are shot at 24 “frames” (still photos) per second, there are nearly 1,500 photos in every minute of video. 

You can imagine that editing, in real time, the thousands of pictures that even a 10-minute movie contains must require a lot of memory. 

But how much memory is needed depends on a lot of factors, including the resolution of your video clips, how complex your movie is, and – perhaps surprisingly – which video editing program you use. 

As a long-time professional film editor, working with multiple video formats and different video editing programs, I have some practical experience that may help you understand these factors and make a decision about how much memory you will need.   

But first, 

What is RAM?

RAM is not a kind of sheep, or a truck. It is a technical acronym (Random Access Memory) — which is nerd speak for the kind of memory that allows you to “randomly” stuff and grab bits of information. RAM is fast, expensive, and absolutely essential for successful video editing. 

If you are wondering why your computer can’t just use all that hard disk space you have, well it can. But memory is a lot faster to access than a hard disk. So your editing program will first use your available memory and then start using virtual memory, which is basically temporary files on your hard disk. 

While virtual memory works just fine, it does slow down your editing because the computer has to constantly swap out all these files between your hard disk and your memory as you work. And that takes time. 

Then why don’t computers just have tons of memory? Because it is expensive. If a MacBook Air costs around $1,000 today, adding just 8GB more of memory to the base model can boost that cost by $200 or 20%! That’s a significant decision. 

So, what do you need to consider before making it? 

Size Matters 

Because memory is used to store all your video clips while you work and process those clips as you make changes to them, the two biggest determinants of how much memory you need is the length of your clips and the resolution of your clips. 

If you have a clip that is a minute long, it doesn’t take much memory. But if it is an hour long, it needs 60 times more memory. 

Likewise, if your clip is the usual high-definition (HD, or 1K) video shot on an iPhone, it doesn’t take that much memory. But if it is a 4K clip or – God Forbid – an 8K clip, it needs, well, 4x or 8x the memory. 

Some simple (and simplistic) math: If a one-minute file of 4K video is around 1 gigabyte (GB), and your computer has only 8GB of memory, editing 10 minutes of 4K video, um, requires more memory than you have…   

Now, in practice, video editing programs use virtual memory, and all the professional Mac video editing apps allow the use of proxies

This very legal sounding word just means that your editor will replace your 4K videos with a smaller 1K version (a proxy) to edit with, and then, when you export your final movie, it applies all your edits to the original 4K version. 

Your Choice of Video Editing Program Matters

Final Cut Pro needs a lot less memory than DaVinci Resolve or Adobe Premiere Pro. Why? 

Because Apple designed not only Final Cut Pro but also the operating system it runs in, the computer it runs on, and the main chips that run the computer. Therefore, Apple can take advantage of every possible way to make everything work together as efficiently as possible. And they do, and the results are impressive.

According to their own specifications, the minimum memory Apple recommends for Final Cut Pro is 4GB (and 8GB if you plan on editing 4K video), while Premiere and Resolve recommend a minimum of 16GB (and 32GB for editing 4K video).  

Remember, these are only recommendations. I have edited 20-minute HD (1K) movies in Resolve on a MacBook Air with just 8GB of memory and was only mildly annoyed now and then. 

But the gap between Final Cut Pro’s need for memory and the other programs’ need is real. Put simply, to get similar speed and stability in Premiere or Resolve I agree with the corporate recommendations: buy twice the memory you would if you are editing in Final Cut Pro. 

Complexity Matters

If you are editing short (under 5-10min) regular HD (1K) movies without a lot of highly complex special effects, and you are using a recent Mac (with an M1 or M2 processor), you will be fine with the minimum memory requirements (8GB for Final Cut Pro, 16GB for Premiere or Resolve). 

I say this because I have edited much longer (20+ minute) HD movies in Final Cut Pro on an M1 MacBook Air with 8GB of memory without any problems or even annoying/distracting delays. No, it wasn’t perfect, but, yes, I loaded those movies with effects, third-party plugins, and whatnot. 

And I have done the same kind of movies in Resolve on the same computer. Which didn’t go quite as smoothly. I was waiting for renders more than I’d like. And sometimes the program was annoyingly laggy. But it ran okay. It didn’t crash. I finished the job. I got paid. 

Now, if you add 4K video to this mix you’re setting yourself up for the perfect storm: Long, Complex, and Big. In these instances, your happiness may come down to your tolerance for delays. So…

How Patient You Are Matters 

If you don’t have enough memory, your editing program will feel slow, laggy, or just a little unstable. And rendering will take longer. 

What is rendering? Well, all that work you are doing in your editor is just a lot of instructions to the computer about how you want your movie to playback. Until the movie renders, you can’t see what all those changes will look like. Most of the time this happens quickly – even instantaneously. But as the movie gets longer, the resolutions get higher, and the effects pile up, you will start to notice the wait.  

There are various studies and tests all over the internet, but the simple bottom line is that your rendering is going to noticeably improve for larger or more complex projects if you double the minimum recommended memory. 

How noticeable? Well, that depends on all the factors we have talked about above, but the simple answer is: You can’t have it all. If you want to edit complex high-resolution (4K) videos into long movies on Premiere or Resolve, you should get 32GB of memory. 

Sheltering Your Memory

You can help your editing program out by shutting down any other programs that aren’t needed for editing. This may sound a little desperate, but I’m cheap so I do it all the time. 

Buried in your Mac is an application called “Activity Monitor”. You can find it in the Launchpad, in the folder which Apple calls “Other”. 

If you click on the Memory tab in the app, highlighted by the green arrow in the screenshot below, you will see a list of every application currently running and how much memory it is using (in the “Mem..” column). 

Notice how much memory seemingly innocuous programs like Dropbox are using? 547.7MB out of my 8GB of memory?! Even applications like Music, Notes, and Messages can add up quickly. 

So if you find yourself running low on memory (and you can monitor the overall usage in the graph and tables at the bottom of the screenshot), try closing some unneeded apps. It may not be a permanent solution, but it can often get through a rough patch.

The Bottom Line

Memory is expensive. And, as the saying goes, you get what you pay for: More memory is better when video editing. So if money is not an issue, my professional recommendation is: go nuts. 

But assuming you don’t want to spend more than you need to, here are my rules of thumb:

If you are editing short films (say, under 15 minutes) in Final Cut Pro on a recent Mac, you will be fine with 8GB, and 16GB would give you room to grow. 

If you are editing long films or know you are going to be doing a ton of effects, you can probably still do it with 8GB but I would encourage you to step up for the 16GB. 

Finally, if you prefer editing in Premiere Pro or DaVinci Resolve, I strongly encourage you to get 16GB and, if you know you will be doing longer or more complicated editing, have a stiff drink, and pay up for the 32GB.

I wish you GodSpeed (or much patience) in your editing and, please, do let me know in the comments below if you are having better luck with less memory or relishing having more! Thank you.