With the latest “Windows critical updates” it is time to revisit the old Windows XP SP2 and Event ID 4226 issue.
With Windows SP2 Microsoft decided to cripple you network performance by limiting outgoing connections to 10 (from previous 60,000+).
You may have applied the popular LVLlord patch but make sure to check your TCPIP.SYS frequently as “Windows Critical Updates” have a tendency to restore/replace your TCPIP.SYS to the crippled one.
TorrentFreak has a good write up that touches many other speed optimising topics.