On 10.9 Safari was resetting (or not using) cache after it restarted. Now on 10.10, if you just close the window and open a new one (without restarting it) Safari won't use cached resources and reloads them from server.
On 10.9 Safari was resetting (or not using) cache after it restarted. Now on 10.10, if you just close the window and open a new one (without restarting it) Safari won't use cached resources and reloads them from server.