Hy Michael,
did you import in Batch or not?
It is important to start larger data sets with using "Import in Batch" and you should set entity specific import options at DMF Framework Parameters, for Example:

The values to set depend on your Batch Server configuration.
With Products V2 and Released Products V2 entity we could achieve import times between 100 to 300 ms per record. So we had about 1,5 hr per 15.000 products.