Our max concurrent searches in four CPUs is 10 (6 base + 4 ). If we open a dashboard with 20 panels, does it just run searches for the first 10 panels and next run the 10 panels?
Splunk will run the first ten searches now, the 11th will run as soon as the 1st search is finished, and so on.
Side note, if you have 20 searches on a dashboard you should seriously look into base searches and postprocessing, as well as splitting that dashboard into understandable chunks.