For those having the same Problem, I just found a solution.
The problem seems to be related to having open too many wallets.
I had 7 wallets open and the sync was way tow slow. 3-4days for a complete resync.
Now I have closed all wallets but one and restarted the client. Now it has alread synced 1/3 in only 10 minutes!

Hope this helps someone, and please excuse my message to this old thread.