Allocation Unit for USB Flash drive

[JimmyNeutron]

Hi,
I did a searched and couldn't find any info in the internet or this forum. Here's my question.

What's the best file allocation unit size for a USB flash drive? My Sandisk USB Cruzer USB flash drive is 16GB.

Vista 64bit defaults its allocation unit to 8K.

I understand the bigger the allocation unit is, the faster the read speed would be, but the more disk space is wasted since a file 9k would waste 7k of space (2 Units = 8k + 1K(7k wasted).

The USB flash drive would be running PortableApps in a file container encrypted by TrueCrypt.

I read somewhere that they recommend 512bytes, but not sure how big of a performance impact that would have.

Has anyone or know any website that did a benchmark on a USB flash drive using different file allocation units with small files, med files, and large files and see what the performance is like in read/write?

Thanks!

 

[gerbiaNem]

Flash drives typically have fast access times, meaning that large AU sizes do not necessarily reduce seek times as they would on a spinning disk. When dealing with space savings, smaller is better also..

Choose FAT16 over 32 for speed purposes on flash from tests I've read (note that for partitions larger than 4GB, only FAT32 will work). NTFS could perform slightly better, but needs to be manually removed due to write caching so I would stay away if you're going to mainly use the drive portably.

Hope that helps.

 

[JimmyNeutron]

Thanks! Given the info, I'm going to try 512 bytes(not kbytes) and try to find some sort of disk benchmarking program and compare that to 4K.

I have to stick to FAT32 primary because I swap in and out of Linux and Windows and my file sizes are sometime over 4GB.