A market analyst for The Linley Group claims Nvidia's Tegra 4 is currently the fastest ARM-based processor, faster than Qualcomm's Snapdragon APQ8064 and Snapdragon 800.
http://www.notebookcheck.net/Analyst-claims-Nvidia-Tegra-4-clearly-outperforms-Qualcomm-Snapdragon-800.89762.0.html