Flutti,
Keep in mind that the mind that the minimum specs have increased when you went to 14. So you may want to increase the CPU and memory.
Also keep in mind that the issue may be the DB and someo of the query tables have not been fully loaded.
Also make sure to clear your cache on the browser.
Otherwise I would reccomend to run the DB statistics checks (Under System) to make sure the tablespaces are in good shape.
Laslty how many Events do you have, if you have over 100K this will have a major impact on queries.
As an FYI, there are some improvments in performance that are coming in 14.6 MP2 and v15.
Ronak