very strange super slow speed behavior

[xplorer]

Hello,

i've been using freefilesync for years and never a problem.
But today, as i'm reconfigurating my harddrives, and implementing some brand new ones, i got so much hassle;

Basicaly it starts syncing ( mirror ) at 140 Mo/s , so ... normal, but then after some seconds or minutes it goes down to 500 ko or so forever ... and i have about 20 To to transfer. i did transfer many to already but now this happend, and i can't do anything about it. + it's urgent.

what i do for now is rebotting my computer, then it's transfering again at 140Mo/s for a short while, then it goes down to close to 0.

Why the hell did it stop working properly ?
when i manualy copy a file, it works normaly at about 140 Mo/s.

i tried different versions of freefilesync, even some older ones ( the new one was so weird, it went down to 0, then stuck then up, then 0 then again and again ) ....

and now i'm trying the 9.6 and it starts at about 4 Gb/s !!! and after some seconds it goes down to 500 ko/s ....

i'm sick of it.

i tried all my disks with the cache enable, then disabled ..
i tried to reset the hot plug to disabled ...

i don't know.

i endly got my new 8 to seagate disks and freefilesync fails me. it happens on all my disks.

i even reset windows to a previous date and it seemed for a while to have solved some problems but actualy not really. it's so random in its behavior.

please help ! Thanks

[xplorer]

Edit, crossing fingers but it appears to have been solved !

i checked some drivers from my motherboard X99 SLI. And i repaired the Intel rapid storage driver, it's perhaps this that caused all my discs to be problematic. i also disconnected the new 8 to disc then reconnected it.

transfering at about 100 - 120 Mo/s now. i hope it continues fine, because yesterday the problem appeared one or two hours later.

using the last version 10.17 now.
i don't know why i see an old file "10.7" ...