The loss of performance is due to the slow resolution time of your Domain Name System (DNS) when DNS is not configured to route to the Internet. The issue becomes visible with SAE 3.5 patch 1 because this is the first version to use the Internal Landmark (DNS name) feature to first determine if every URL is part of an internal website or not. To do so, the Internal Landmark features calls the Windows API (Application Programming Interface), which uses the GetAddrInfo function to do internal name lookups. If your DNS does not route to the Internet, processing these lookups will be slow, which in turn affects the speed at which you can browse.