Rational is bullshit - iphone ram demand is a minute fraction of world demand.
Can you say cartel? Happened before, will happen again - google "DRAM price fixing" or "memory cartel" and form your own opinion.
Earthquake in Taiwan (8 Apr 2013) affected production - but that doesn't explain the rise.
Let's name the bitches last time (€331m fine - http://europa.eu/rapid/press-release_IP-10-586_en.htm
, also multi 100m$ fines and multiple admissions of guilt in the US too..) : Micron, Samsung, Hynix, Infineon, NEC, Hitachi, Mitsubishi, Toshiba, Elpida and Nanya
But maybe I'm just a paranoid crank this time? State of California and 32 other states don't think so eg http://www.law360.com/cases/50769e27e9be1a076500438d
etc etc. Last time the proceedings took 8 years - so don't hold yuor breath for a legally binding decision