In a recent article in the “International Business Times” titled “Apple iPhone 6 Plus Keeps Crashing, Owners Say, Especially 128GB Model“ there seem to be some problems users are experiencing with the new machines. Likely this Is related to memory and the way memory is managed in the new system. 128 meg memory seem to have further problems around crashing and this might support the memory model theory.l
IOS 8 and Yosemite Major
IOS 8 , icloud and Yosemite are major revisions are the operating system level. These revisions add a new dimension to the sytem experience but also might be at the root of the crashing.
Apple will likely stabilize this especially as they gather more information and eradicate that which is problematic. There is much to like in this new system but often significant change comes with problems. I have no doubt they will be eliminated.