I just bought the same 512MB "SanDisk Cruzer micro" and thought it was very slow on a fast system with USB 2.0. Now you have me wondering as I did not test the transfer rate and did have something running in the background. Note this is a different and cheaper product, than the older 512MB "SanDisk Cruzer Mini".
My initial reaction to the slow speed was that Flash writing is a lot slower than reading and simple test proved that.
This forced a lot of research into bench marks and such. Got interesting. First it depends on your USB port and its speed. Not all USB 2.0 ports are High-Speed. Some are no faster than the USB 1.1 speed of 12Mbit/second. So that can effect your performance of a USB Flash drive. You really need the the High-Speed version of USB 2.0.
USB 1.0 1.5Mbps = 187KB/s
USB 1.1 12 Mbps = 2.25MB/s
USB 2.0 Full Speed 12bps
USB 2.0 High Speed 480bps = 60MB/s (in theory)
So lesson one: find out how fast your USB port really is.
Next, Flash write speed is slower than read speed and this can vary with different vendor products, but more important is that the effecive speed depends on the size of files you are reading and writing.
512 byte reads are in the 200KB/s to 600KB/s range
2MB reads are in the 4MB/s to 10MB/s with some like the new Sandisk Titanium hitting 15MB/s
Things really slow down on small writes:
512 byte writes are in the 2 to 5KB/s range.
Thats is KB, not MB.
But once the file size is above 2MB the speeds can range from 1MB/s to 9MB/s
So lesson two: writes are a lot slower than reads, and smaller files are very slow.
So your results will vary depending on how fast your USB port really is, and the size of the files you are writing.
If you want to study a good benchmark test of different products (SanDisk cruzer mini, not the micro) with charts on how different products do with different read/write sizes on a High-Speed USB 2.0 adapter, then look through the seven pages of this USB 2.0 Hi-SPeed Flash drive roundup.
The slow speed of small file writes may seem strange until you think about it. But the USB Flash drives to be compatible with any system they are put into still have to use the FAT32 file system. So not only the cluster of data is written for each file, but several reads of the Directory table(s) and FAT tables must be made for each file along with the write to update the Directory entry and the FAT table entry(s). Because of this, large file writes will be more efficient.
