The effect speed will depend on two things:
a) speed of the transitions itself
b) duration of the twitter widget and if duration per item is enabled.
For example, let’s say you want that widget to return 10 tweets
If duration is set to 10s without duration is per item enabled it will try to display all those tweets in 10s, ie ~1s per tweet, if you have an effect enabled then player will need to make those transitions very very fast.
if duration is set to 10s with duration is per item enabled, then each item will stay on the screen for 10s