performance problems with raid10,f2

Hi

I have a 4 drive array with 1 TB Hitachi disks, formatted as raid10,f2

I had some strange observations:

1. while resyncing I could get the raid to give me about 320 MB/s in
sequential read, which was good. After resync had been done, and with
all 4 drives active, I only get 115 MB/s.

2. while resyncing, the IO rate on each disk is about 27 MB/s - and the 
rate of each sdisk is about 82 MB/s. Why is this?

best regards
keld