1.5GHz implies it won't be Cortex-A15 based and Samsung means not Krait.
I mean, look at this performance:
http://www.anandtech.com/show/5559/qualcomm-snapdragon-s4-krait-performance-preview-msm8960-adreno-225-benchmarks
If I was paying $600 for a phone I'd want the best CPU on the market.