Formatting 32GB USB flash with exFat

By Geepers ยท 5 replies
Nov 10, 2011
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  1. Noticed on the forum some advice to format ALL Flash Drives with FAT32...

    I just bought a new 32GB Flash...and noticed on other web forums
    stating that you can also use the newer 'exFat' mode...

    My questions are: Which format really IS better for this size in storing pictures/audio files
    up to the 29.8GB limit it says on the flash...

    ..and when I use either one: what ALLOCATION UNIT SIZE choice is the best for each mode?

  2. jobeard

    jobeard TS Ambassador Posts: 11,173   +989

    hmm; normally (especially with FAT) we just specify the filesystem type without any options (like allocation size, sector size ...). If this were a NTFS filesystem, those options would be very useful to set larger sizes for large files.
  3. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +422

    If you aren't dealing with files over 2GB I suppose you could get by with FAT32. It can be read by nearly any system you'll encounter. If you use NTFS and put it in a Mac, the Mac (likely*) won't be able to write to it, but it will read just fine. ExFAT though, it can have big file sizes and is read by Windows and Macs**.

    Like jobeard said, choose big sector size (or allocation size like your post said) if you are dealing with large file sizes. Don't use it if you have a whole bunch of files that are a couple KB in size or less, otherwise they will take up more space (if you told it to use 16KB or 64 or whatever size).

    *You can enable NTFS writing in OS X through some command line stuff, but its a pain. You can also get MacFUSE and NTFS-3g and enable writing that way.
    ** Snow Leopard and Lion can read and write to exFAT, but for compatibility between OS X and Windows, you need to format the drive as exFAT in Windows before using, if you format it as exFAT in OS X then Windows can't read it.
  4. Geepers

    Geepers TS Rookie Topic Starter


    YES -

    MOST of my files will NOT be bigger than 2GB 'on' the 32GB Flash,
    but some will be large MB files...

    I already formatted this (now) with Fat32 [default it says],
    with a 64KB Allocation Unit Size; Holds storage up to 29.8 - Would THIS be good for now?..

    Also RE exFAT: Will this new/recent kind of format work on ALL Windows OS - including XP?

  5. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,742   +422

    You should be fine then. I think I misspoke with 2GB, FAT32 should be good for up to 4GB, you will not get any files on the drive bigger than 4GB with FAT32.

    exFAT does work in Windows XP, but I haven't had an XP system in a long time so I don't know if its a Windows Update you can just get automatically or if you have to intentionally go out and get it.

    This page has exFAT driver support dls for XP, as well as some information on the benefits of exFAT.
  6. Geepers

    Geepers TS Rookie Topic Starter

    Follow-Up (2)

    Yes, currently I'm on a Samsung Netbook N150 with Win7 Starter..
    ..CHEAP OS, I know...but seems to be quite effective...

    What you're saying is that FAT32 format should be good
    for up to 4GB of 'FILES' ON the Flash?...

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