I used to run a Jenkins server with about 10 jobs with full history (~ 500 builds).

1.480.3

Server start -> wait for 1 min -> login -> dashboard
Loading time was decent (<1min) and memory usage is about 1GB.

1.509.2

Server start -> wait for 5 sec -> login -> wait for 10 min -> dashboard
After updating WAR to 1.509.2 and all plugins to latest version (like dashboard to 2.8), loading time is horrible (10min) and memory usage is about 4.5GB.

Navigation is faster, it seems that all data is in memory but I have to get back to 1.480.3 because such loading time and memory consumption is not acceptable on my jenkins server.