OWB running together with BIEE

Good Day,

I just want to ask is it really not an ideal scenario to have both BIEE running/generating its reports and OWB starting an ETL to run all at the same time? Because currently where having a long time finishing ETL on OWB (e.g. an ETL process that takes 1 day could take 3 days when running together with BIEE) when we run it together with BIEE. So my question is, is there an other way where we can run both BIEE and OWB at the same time without slowing down the system? Thanks!

NOTE: we already have 4 dual cores and has a mem of 16GB. Our OS version is Windows Server 2003 Standard Edition.

Lan