Solution : https://service.sap.com/sap/support/notes/568908 (SAP Service marketplace login required)
Key words : 
goto -> activate statistics -> select kernel application statistics, component xx-ser-tcc-crm, application servers support ascii codepage, mysap crm initial download configuration, select middlewaremessage flow statistics, middleware message hub statistics, /swcenter -> sap support packages, activate crm middleware statistics, move significant data volumes, fastest data transfer modedisadvantage
Related Notes : 
       
| 634263 | Selects with FOR ALL ENTRIES | 
| 536414 | CRM 3.0/3.1 SAP Composite Note: Middleware reorganization | 
| 430980 | CRM Server: Analysis in delta data exchange R/3->CRM | 
| 429423 | CRM Release: General analysis of the initial Load | 
| 350176 | CRM/EBP: Performance improvement during exchange of data |