Well, first off, the 'ppl get thrown in the air' thing is an established bug with the skyrim engine. Observe lol
As for the things that are flashy, are they constantly flashy no mater where you stand or look at them in the game? Are the same things constantly flashing? Memory related artifacts won't be constantly flashy, they last literally less than half a second and rarely appear in the exact same place more than once. They usually aren't just a single color either, most often memory related artifacts are green, blue, white, and purple (in order of prevalence). If you can stand still in one spot and see something constantly flashing, it is probably just a problem with the game and not your overclock. Just save your game in an area where you see a lot of flashing, close the game, revert your overclock to default value, re-open the game, and load your game. Now check for flashing. If it's gone it might be memory related, though it might also just be because you restarted the game. So just to be sure, close the game again, reload your overclock settings, and then open the game again, and load your save. If the flashing is gone still, then it's probably not your overclock. If it's back after re-overclocking, then it's probably your overclock.