The delays can be due to the reporting that is selected, such as 1-month gain, 3-month gain, 1-year gain, or the time period for investment performance.
Consider what is being presented in the displayed tab and possibly the tabs available.
Try selecting an investment reporting screen (or any report) that does not require all these performance calculations to be updated live. This may improve the update rate.
(you did not indicate what you were updating; transaction lists or share prices ?)