[Q] Qualcomm S4 - Javascript optimization.

The general opinion is that the Krait based S4 is a terrific SoC, however its javascript performance is currently lower than its rival

For example

S4 1.5 Ghz Xperia T running stock Cyanogenmod 10 browser = 1381 ms ~

Nexus 7 (Tegra 3) overclocked to 1.6 GHz on stock AOSP browser (4.1.2) = 1100 ms ~

Galaxy Note 2 (Exynos) at 1.6 GHz on stock Samsung browser = 975 ms.

I would have thought that the Krait architecture at a similar clockspeed would beat a A9 SoC. What is the likely cause of this discrepancy and will firmware / software updates resolve it?