Hello Alex,
You urself can check in detailed DTP log where the DTP is taking time. Expand the DTP request to see exact time spent in eact step.
Also in the DTP, click on debugging and go line by line to see in which code system is taking time.
There are ways to optimize DTP performance. Go to RSBATCH for standard DTP settings like increasing the bck process.. also check if there are any routines where optimization can be done.
Regards,
AR