[justincormack]

Copying in cache is very fast now. Spending time aboiding copies is no longer always a win like it used to be.

[bzbarsky]

In cache is key, though.

Decoded image data is 4 bytes per pixel, so a raytraced image of any sort of reasonable size would barely (if at all) fit in L3 cache even on modern processors. And you need to fit both the source and the destination, right?