Originally Posted by Brutuz
The differences aren't all that great, iirc the 600 is mostly just a revision with a new naming scheme.
S4Pro (APQ8064) uses Krait(200) architecture, clocked at 1.5Ghz, supports dual channel LPDDR2-553. Snapdragon 600(APQ8064T/AB) uses Krait 300 architecture, clocks up to 1.9Ghz and supports up to dual channel LPDDR3-800.
A little more than a revision with a new naming scheme even though both are quad core Krait with adreno 320, the core architecture & IMC both changed.
As far as Krait 200 vs Krait 300, from Anandtech's HTC One review
Edited by sherlock - 6/14/13 at 9:34pm
In general, Qualcomm claims we should expect a 15% increase in CPU performance at the same frequency for Krait 300 vs. the og Krait. Factoring in clock speed improvements and you're looking at 25 - 30% at the high end. To find out just how much of an improvement exists in the real world, we once again turn to a combination of microbenchmarks and the usual set of web browser and native client tests.