Since updating Safari to 10.0.2 on El Capitan, I'm experiencing huge memory leak issues. Safari, would become unresponsinve and fail to shut down without a Force Quit. I cleared the cache and reset everything but to no avail. Then El Capitan gave me an Out of Memory dialog box, after Safari had been open in the background with no tabs open for a few minutes. After a Force Quit, I opened it again and checked it in Activity Monitor and watched as the used memory climbed by about 30Mb a second. I have had to switch browsers for the time being. Hopefully someone at Apple can come up with a fix soon.