The rate you quoted works out to between 6 and 7MB/sec, which is a pretty decent speed for USB flash memory. A lot of flash memory is even slower than that. If that's not fast enough for you then then you'll have to look for a faster drive. For example:
What kind of flash drive is it? If it's an plain-jane drive I really don't see how it could format significantly faster on XP unless it was a quick format.