Warning! Technical stuff ahead! We use a lot of external drives for media work and storage. We’re constantly handing projects off to different people to work on different parts and that means these projects need to be mobile. It also means that they need to work on both PC’s and Mac’s. To do this, we reformat all our drives to exFAT which allows us to read and write to the drives using either a PC or a Mac. Very handy.
Now, the question I’ve always had was: 1) What allocation unit size should I pick for exFAT? and 2) Am I loosing read/write speed when I pick exFAT over NTFS?
For question #1, doing a Google search gives you some answers, but also leaves you with a lot of head scratching. First, a lot of people confuse the default NTFS file size of 4096 bytes with the exFAT option of 4096 kilobytes. These aren’t the same!!! 1 kilobyte = 1000 bytes (or 1024 bytes depending on context). So when I reformat to exFAT, I typically pick 256 kilobytes for the Allocation unit size. It’s the default the computer picks for me and I’ve read several places where it was at least alluded to being a good size. There is no right size, there are tradeoffs, but for us, it works just fine.
For questions #2, I’ve always been concerned that I may be limiting my speed when I pick the exFAT format vs. the NTFS. There are read/write tests on the web that break all this down, the problem is that it doesn’t really answer my question for me, it basically says it all depends on the type of files being used (not to mention the people who contradict each other). So, when in doubt, test it out. I grabbed a 11.2 GB folder full of various video files and project files and copied it to the drive when it was formatted as NTFS and exFAT. The NTFS took 130 seconds to move them over while the exFAT was only 107 seconds. I then exported an edited video file using both formats. The exFAT took 118 seconds to export the project, while the NTFS took…. 118 seconds. I’m doing this off a stop watch, manually clicking buttons, but from what I can tell, there wasn’t a difference between the two on typical projects we work on.
That answered it for me. exFAT gives us the option to work on either a PC or a Mac and it may be a bit faster for us and the type of work we do. As for the Allocation Unit Size, I’m comfortable with the 256 kilobytes size. Hope this helps.
Adam Kilbourn 🙂