I just heard that the 840 pro failure problems have been fixed. I immediately decided I should replace my 830 and was about to buy a 512gb 840 pro when I thought I should slow down and inquire here. Couple things. 1. I heard that the 840 uses cheaper memory than the 830. Is that true for the 840 pro also? and 2. Is the upgrade to the 840 pro worth 50 dollars? cause thats how much I would have to pay to exchange for the pro.