What do u mean "a lot of small files"? Aren't you testing sequential performance? Btw it's possible the drive you're copying from is to blame....
Now I'm copying everything back to RED PRO. "a lot of small files" means my photos and MP3 files. The write speed does not depend on source drive. I can see slow speed while copying from SSD or high speed from eSATA HDD - and vice versa of course. It looks unpredictable for me.
If copying lots of files is slow from the SSD but fast from another HDD it could be the SSD's random read performance holding you back. But tbh 90MB/s write speed isn't bad......
I can see all possible speeds (range 30 - 100 MB/s) regardless the source drive. The slow SDD and fast HDD are just an extreme examples. However now it looks better than before. The speed is mostly quite good (70 - 100 MB/s) and only sometimes drops down to 30-40 MB/s.
And what I did? - drop volume - HDTune read/write benchmark - re-create volume (GPT, one big partition) The disk is considerably faster now. I hope this improvement will be permanent.
The last note: it seems that a partial culprit was the service "Acronis Nonstop Backup Service". I use Acronis TI 2011 Home with disabled nonstop backup but this service has been active and sometimes the process afcdpsrv.exe generated a big HDD load when vmware was running. Now I can achieve 120+ MB/s even during copying from/to the same HDD partition.