Slow DCRs, Workflow.

System

I'm setting up a TS6.5 instance on new hardware and am experiencing odd behaviour with the DCRs and workflows. They work fine for me and anyone in my domain, but for colleague's domain (which is 30 times bigger than mine) it is terribly slow. Login times are fine however and group caching is set. Could there possibly be some cache settings I'm not considering? Any ideas? Thanks in advance.

Brian

(TS 6.5, Windows 2003)