DDR vs SDR ?

If I change my Drobo S, from SDR to DDR, I was wondering:

  1. In terms of performance (write and read access), will there be a reduction of MB/s ?

  2. If yes, how much on average will the MB/s reduce when switching from SDR to DDR ?

write its very small, read i dont think there is any noticeable difference

i think dri have said less than a 10% hit.

Less than 10% sounds good, for extra level of protection with DDR.