The OnePlus 6 prototype that is featured in the GeekBench results is powered by the same Snapdragon 845 SoC that comes with the Galaxy S9+ (US version) and Xiaomi Mi MIX 2S and it also features the same 6 GB of RAM. Apparently, the OnePlus 6 prototype might be using an overclocked SoC or better memory, and the final product could end up even faster.
https://www.notebookcheck.net/OnePlus-6-beats-Samsung-Galaxy-S9-in-leaked-GeekBench-results.292592.0.html
Doesn't beat my S9+(Exynos version). I get 3663 single core and 9091 multi core.
side note: they have cheated on benchmarks in the past :v