Big delay in web service response

Hi,

I have experienced a strange slow response when calling a WCF web service. Below is an example: sometime it takes about 5 minutes before the message arrived in the orchestration. The message size is not big, around 2 KB. This happens when other web service functions are calling as well, but this web service function is called more frequently.

We are using BizTalk 2009 and our test machine contains only a couple BizTalk applications. When I am calling this web method function via SoapUI, then it responses quite fast. Even with multiple calls per 250 millisecond.

Does someone have encountered the same behavior like this?

Thanks,
Tuan