Thank You guys.

Tamilselvan: "For direct load option, I use the following three parameters carefully.
streamsize=1048576 readsize=1048576 columnarrayrows=8000"
How to decide which is the best option?

William: I did raise parallel mode, but our DBAs don't want to tamper the current applications.

I dont hv any other option other than tunning this job in DIRECT MODE.

Cheers