Should also remember the more you use any flash storage media, it slows down and it slows down on thumb drives really dramatically. Because on flash media, you cannot overwrite existing data, it must first be erased. There is another issue with erasing too... While you can read and write to 4k pages, you can only erase 512k blocks.
But Windows can only transfer files as fast as the medium its talking to will allow as well as the max though put of the connection.
I have the same problem, sandisk 16gb transfer speeds star at about 16mb/sec the slow to a max of 2.5mb/sec, no matter the file size or type, and I only bought it 6 days ago, so wear is not the prob.
File transfer also from PC to USB also matters with the number of files it is copying to. The more, the slower. But you can install programs in your PC that will speed up file transfer. There are a lot of programs in the internet.
Do you have Microsoft Security Essentials? i had this problem since last month and fixed it as a temporary measure by excluding the USB drive or flash drive in question (Example G:\) from the real-time scan.
Yep also changed the cluster size and my through put is flying!
Was 1.5 Mb/s - now running between 20 - 50 Mb/s for a 64bit cluster size.
Remember to change the cluster size when formatting from fresh, or convert the cluster size using something like Acronis Disk Manager.
Quote