Hi Amit,
TEST1
1)Try to increase the array fetch size in source to 5000 and in target rows per commit in BW to 5000
and run the job and see if the records are loading fast
TEST2
2)If the test 1 fails then just use an SQL transformation and just import the table inside it.
Select * from the table and use the query tansform and map the columns to target and load the data
See the run time and check how fast th data is loading
TEST3
3)if test 2 fails then try to create an view and use only what are all columns that you require for the target. because if you use the other columns that are not required in target that may also cause the issue in performance.
TEST these three scenarios and let me know your results
Regards,
Prasna