Well here is something else to try. Make sure the connection at the main computer hasn't downgraded its speed (despite having a 1 Gbps Cat 6 ethernet cable).
One time, my main computer scaled back to 10 Mbps (100 times slower connection) due to a power save issue or something). This would then affect all computers amazing charts speed, especially when starting up.
ANyway, here is how you can check this.
On the tray of the main screen, right click the networking icon. Choose open network and sharing center. Left click "change adapter settings" and right click "Local Area Connection" Status and you should see a speed listed. It should hopefully be 1 Gbps. It is shows 10 Mbps you may have found an issue. I don't think this will fix your pdf issue however.
