I have the same issue. Support directed me to do a speed test for my connection at http://speedtest.xmission.com/ . After running the test a number of times at different times of day, it appears that my internet connection is inconsistent and the chart delays occur when there is a connection slow-down. Currently I have a portable modem that fluctuates wildly and I am changing to high-speed DSL (8.0 mps download; 700 kbps upload). I believe the minimum connection recommendations are 3.0 mps download and 256 kbps upload -- consistently. One other thing - avoid connecting to your modem via wireless router; this can cause issues as well. Connect via cable if at all possible. It's old-school but it's the most reliable.
Hope this helps.