Extending articles problem through lsmw

Dear Gurus,

We facing problem for extending articles in our production server.

Previously for extending 8000 articles it used to take around 1 to 2 hours time [this is six months backup] but now for extending 1000 articles its taking 6 to 7 hours time.

we using it as background job.

how can we disgnose the problem.

Does anybody faced such kind of problem?

Thanks in advance

Regards

santosh