Drobo-2 USB Speed

I copied the data off my 2nd Gen Drobo (connected via USB on a Win7 machine) so I could change the volume size from 2TB to 16TB, since I no longer need WinXP accessibility.

While copying my files to an external hard drive (via USB) I noticed the transfer speed was 12.5 MB/second. I reset the Drobo and began copying the information back and now the transfer speed is a solid 20.8 MB/second.

The other tasks being ran on the computer was identical both times. Is this a normal speed change for being formatted under Win7 vs WinXP?

you might find that when you are starting to write to an otherwise empty drobo, it is mirroring the data rather than doing parity - it wont start doing parity until it passes the 50% full mark

which would explain your increased speeds

yup, and when you reach 95% or more (97% in my case) it starts to go fairly slow