[ars]

> Source?

It's poor form to ask for a source of something that would take you 15 seconds to google.

> Allegedly, Cree has developed a white LED with up to 254 lm/W

Interesting considering that the theoretical maximum is 251 lm/W - so I wonder which law of physics they violated to do that. (Most likely it's not actually white, but reddish.)

And this time I will give you a source since this is a tiny bit harder to google http://physics.ucsd.edu/~tmurphy/papers/lumens-per-watt.pdf