On AnTuTu, we can easily see how the Helio X20 outscored the Helio X10 by 40%. On GeekBench3, measuring the performance of each chip's CPU, the Helio X20 scored a single-core tally 70% above the Helio X10. For the multi-core score, the newer chip had a more reserved 15% improvement.
Moving out of the MediaTek family, the Helio X20 trounced the Qualcomm Snapdragon 810 in both single and multi-core results. Compared to the Exynos 7420, the MediaTek chip out performed it as well. A new unannounced Exynos 8890 chip being tested by Samsung on the Lucky-LTE device (which could be the code name of the Samsung Galaxy S7) scored well below the Helio X20 with a single-core tally of 1336 and a multi-core score of 4824. Compare that to the 1835 and 5884 single and multi-core scores produced by the MT6797, the Helio X20 chip being tested with the HTC One A9.
Recently, the Snapdragon 820 SoC was spotted on running on Lucky-LTE (Galaxy S7?). Allegedly an enhanced version of Qualcomm's next high-end chipset, the SoC produced an AnTuTu benchmark score of 72,355 to top the Helio X20's results for the same test.
Regardless of how the new generation chips score on benchmark tests, it seems like we can all be assured of some zippy behavior on the new high-end handsets set to be released later this year and into 2016.
source: MyDrivers (translated) via Techgrapple (1), (2)