Use the trace flag 8721 to determine how often that AUTOSTATS runs
One way to determine how often that AUTOSTATS runs in SQL runs is to use the trace flag 8721. When turned on, it outputs to the errorlog every time AUTOSTATS runs. This information can be used to help determine if AUTOSTATS is running too often or not. Be sure to turn off this trace flag when you are done with it, as it can produce unnecessary overhead.