It can get pretty frustrating when the flash games that you love to play starts to lag or play out a lot slower than it usually does. There is no reason set in stone as to why this happens, but there are a few different ways to fix it. Or at the very least try to. To bring your games back up to the speed that you deserve, you can try out a few of these things and hopefully one of them will work for you.
The first trick is to lower the quality of the game that you are playing. To do this is actually really simple, all you have to do is right click while you are on the game and go down to quality. Whatever this is set at, make it the next step lower. If you are on high, put it down to medium and see if that helps, and continue going down if needed.
If that trick doesn’t work, you can do the same right clicking trick and zoom in or out of your flash games. This might help it if there is a lot happening on the current scene and your browser can’t keep up with it.
If neither of those work you should make sure that all of your flash players and java scripts are up to date. If they aren’t then get them updated. If they are up to date, un-install them and install them again. They might just need a reboot.
Though if none of these tricks work for you, you can try to see if the flash games will play on a different browser. Different browsers have different requirements as far as playing videos and games so it might a browser thing more than it is a java or flash problem.