can you run the following command on both machines and post back the o/p?
netsh int tcp show global
also can you post the o/p of:
fltmc
and a screenshot of start->run->ncpa.cpl->properties of network connection->configure->advance.
Last we will need events from eventvwr.....see any relevant events from application or system log.
Team viewer is good if you work remotely ,but, nothing beats rdp when working internally....I use it all the time