Regarding Flash updates, I received notice of a new one a few days ago. I did not allow it to install, so I can't speak for its efficacy. I'll install it one of these days and check it out.
Regarding browser cache, it is supposed to store an item. When that item is accessed again, it is supposed to check the original source (at the URL) and compare its date/time to the cached version. If the original hasn't been changed, the cached version is supposed to be used, thereby cutting out the time to download the item.
THIS DOES NOT ALWAYS WORK PROPERLY. Many times, when I am designing a web page, I'll change the original but the browsers will continue to try to use the cached version. I have to manually clear the cache to get the new version. If you're having meter problems, go ahead and clear the cache. It may or may not help.
When you load a page, the page will normally refer to other objects (graphics, scripts, style sheets, etc.). These are loaded on separate connections. Nowadays the separate connections usually are run by separate threads (a thread is a sort of mini-process). Consequently, even though the graphics for a new stroke have been loaded and displayed, additional activity may still be taking place. This is why waiting to start the stroke until activity has calmed down may be beneficial. A look at your cpu activity is beneficial in this case. You can also check your network activity; however, it is usually also visible as cpu activity.