Graphical issues: the PS3 or the game?

[toef]

Recently I've noticed some weird graphical quirks when playing some games. They come in two different varieties, which I'll explain separately.

Problem 1: Stick/poke graphical problem

With this issue, there is sometimes some random, solid colored, skinny, stick-shaped thing sticking out of an object.

Games I've noticed it in: Lego Rock Band, Assassin's Creed II

In Lego Rock Band, I was being chased by a dinosaur (I think), and whatever color it was (I think it was green), there was a skinny stick-shaped green line extending all the way to the edge of the screen, as if a piece of the dinosaur was being stretched.

In Assassin's Creed, I was playing an early mission, and a tan colored stick was extending from the side of a guy's face, out approximately 3-4 feet (in game dimensions, not real life).

Problem 2: Twitching/flickering graphics

With this issue, small parts of something within the game will flicker or twitch.

Games I've noticed it in: Dragon Age: Origins

In Dragon Age, I was playing as a dwarf, and during one cut scene, the dwarf's sister's head would flicker. At another point in the game, a random barrel in the background would flicker in and out.

This happened in another game a few months ago, but I can't remember which game anymore.

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So my overall question is: are these problems just problems within the game, or is it indicative of a problem with my PS3?