Duplicate jobs between OST device take long time since SP3

BE2012 SP3

1 CASO and 2 MMS

2 DR4000

Since SP3 was installed into our BE 2012, we experienced new behavior in duplicate jobs:

Before : The speed of duplicate jobs was fine. No delay to load media and high backup speed between DR4000. But 2 duplicate jobs won't run (the biggest one) and I need to run it manually. This is the reason we upgrade to SP3. SP3 fixe this issue...but...

Now : The SP3 is in production and the speed of duplicate jobs fall's dramatically. Not the real speed used by the duplication step but now we have a time to wait for "Loading Media" step. A waste time indeed.

Please, don't tell me : it is time for waiting about SP4 !