Can't reproduce it here.
7.1 is slower, but not noticable.
Do you have the UPnP settings enabled?
mIRC 7.1:
It took 0.063 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.078 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.063 seconds for test_socket to open.
It took 0.078 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.078 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.078 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
It took 0.078 seconds for test_socket to open.
It took 0.062 seconds for test_socket to open.
mIRC 6.35:
It took 0.032 seconds for test_socket to open.
It took 0.047 seconds for test_socket to open.
It took 0.046 seconds for test_socket to open.
It took 0.032 seconds for test_socket to open.
It took 0.046 seconds for test_socket to open.
It took 0.047 seconds for test_socket to open.
It took 0.031 seconds for test_socket to open.
It took 0.031 seconds for test_socket to open.
It took 0.047 seconds for test_socket to open.
It took 0.031 seconds for test_socket to open.
It took 0.031 seconds for test_socket to open.
It took 0.031 seconds for test_socket to open.
