Here’s a comparison between the Nokia Lumia 520 and the Nokia X. Both competing in similar segments. The Nokia Lumia 520 brought the popular 620′s winning feature combination to an even lower price point, resulting in the 520 becoming the best selling smartphone in its price range.
The Nokia X aims to achieve the same if not better success.
When I played with the Nokia X, I did wonder how come the games appeared to load quicker than expected.
Performance wise, the Nokia X is pretty good for a budget Android. The Nokia Lumia 520 appears more consistent. Camera wise, the 520 has the same UX as higher end lumias, i.e. there’s no stutter or lag with the camera. Look at that awful frame rate in the Nokia X (I think that’s the viewfinder in video mode? Video mode when on some kind of battery saving mode makes the frame rate Level:potato).