I had the same problem. Response times were extremly slow and refreshes worked quickly, most of the time. All suggestions made by bicycle didn't help. What seems to help best so far (no slow response times for the last 30mins) was to reset winsock as explained here: http://www.devside.net/wamp-server/wamp-is-running-very-slow
netsh winsock reset
netsh int ip reset C:\resetlog.txt
You need to restart after this.