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I tried exFAT in order to use my external hdd on both mac and windows but I found it's so much slower than HFS+. The speed is noticeably different when I tried to fast forward movies (over 4gb).

exFAT was recommended in this question.

Community
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Tuan Anh Tran
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  • There also is a heavy i/o speed decreate when accessing exFAT formatted volumes through Java applications. We have got experience with CrashPlan that moves exFAT located archives roughly 5 times slower compared to archives stored on HFS volumes. – Pro Backup Jul 24 '12 at 13:29
  • Did you format your disk with Windows or with Mac OS? – codingFriend1 Dec 11 '12 at 09:19

1 Answers1

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exFAT is a file system optimized for flash drives, meaning storage devices without moving parts where seek times are constant. It sounds like you're using it for a mechanical hard drive – which is what's causing the poor performance that you're experiencing.

You should reformat the drive to HFS+ or FAT32 and only use exFAT for solid-state drives.

ref: http://en.wikipedia.org/wiki/ExFAT

annawie
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  • Why only SSD? Does that include SSD drives or just flash drives? – William Jan 29 '17 at 22:47
  • @William SSDs (solid state drives) are flash drives (a.k.a they're built with memory -flash- cards instead of a rotatory disk with a mechanical head). With HDDs, you have to wait until the head is on a specific sector to start reading data, but flash drives (SSDs or whatever) read almost instantly. exFAT is designed to use that second type of hardware. – Alejandro Iván Mar 16 '17 at 04:45
  • @AlejandroIván hmm I'm sure flash drives don't have the same read and write life span of SSD but that might be true. So if exFat is the new Fat32 why is it only intended to work with SSD then? – William Mar 16 '17 at 15:33
  • @William that's probably true, but in general when you talk about "flash" drives you're talking about storage based on memory cards rather than rotatory disks. exFAT is way more powerful than FAT32, for example, it doesn't limit you to 2 GiB per file like FAT32 does. It is intended to work with SSDs, but it can work with HDDs (it's just slower). I actually prefer using exFAT on all my removable devices (including a mechanical USB HDD), since it's compatible with Windows (XP and up), Linux and macOS as read-write (probably installing some packages on Linux, but nothing too complicated). – Alejandro Iván Mar 16 '17 at 15:37
  • @AlejandroIván Yes same reason I'm trying to convert to using ExFat. Here is the issue I'm running into http://apple.stackexchange.com/questions/270850/mac-osx-cant-repair-the-disk-exfat we can continue the discussion there if you have any idea – William Mar 16 '17 at 15:44
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    @William ah, that. For some reason, Windows formatted exFAT usually have problems on other systems. The best way to make it work is to re-create the partition from macOS. At least that happened to me like 2-or-so years ago. EDIT: Of course, backup your data before doing anything else (I know it seems obvious, but sometimes even experts underestimate this and then lose all data... it happened to me once too). – Alejandro Iván Mar 16 '17 at 15:46
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    I don't believe this answer is correct. It is correct that exFAT is "optimized for flash drives" (according to Microsoft) - although those optimizations actually are quite minor. However, the conclusion in this answer that when the system is optimized for flash drives it must mean worse performance on non-flash drives - that is not correct. The optimizations in exFAT for flash drives do not diminish performance on non-flash drives. – jksoegaard Jan 06 '22 at 10:32
  • FWIW i got a cheap 12TB SSD off ebay (chinese) formatted to Exfat, and it transfers really slow from my SSD mac. it didnt allow me to format as APFS. in fact the format process failed from mac and i had to do a quick format to exFat from a windows machine where the full format also failed. it only worked when i quick formatted it to 1024kb blocksize link relevant cos its nothing to so with mechanical device to SSD, other variables like formatting and quality of device can effect speed. – jsky Jun 29 '22 at 05:17