The iPhone 6s gets a single-core Geekbench of 528 while the Nexus 6P gets 208. The Nexus 6P's multi-core score was 520 - less then the iPhone 6s' single-core score. The iPhone 6s' multi-core score was 970 - 87% higher than the Nexus 6P.
Yep, it had 8 cores. Good for it. It was still a lot slower.
https://www.anandtech.com/show/9820/the-google-nexus-6p-revi...
AnandTech also found it a lot slower. Mozilla's Kraken web browser benchmark took 2.4x longer on the Nexus 6P. The iPhone scored around 1.9x higher on Google's Octane benchmark.
It's really hard to argue with Apple's superior processor performance. I guess if you're looking for more cores with inferior performance, the Nexus 6P fits the bill. MORE CORES!