Well now this is interesting. Leaked benchmark tests appear to show that the as-yet unreleased OnePlus 5 is much faster than the Samsung Galaxy S8 and Samsung Galaxy S8+, as well as the Google Pixel and Google Pixel XL.
Currently the Google Pixel and Pixel XL are some of the best performers despite using older Qualcomm Snapdragon 821 processors; but they run pure Android Nougat and have been specially tailored by Google. The Galaxy S8 and Galaxy S8+ were the first devices to market running the new flagship Qualcomm Snapdragon 835 processor, at least in the US market - the international model runs Samsung's own Exynos hardware, but it's based on the same 10nm architecture.
But although the OnePlus 5 runs the same Qualcomm Snapdragon 835 processor as the Samsung Galaxy S8 series, it is, according to the leaked benchmarks, outperforming both Samsung's and Google's flagship models.
The benchmark was outed by TechRadar and shows that in terms of app opening speeds, the OnePlus 5 has everything else beaten. It will be interesting to see what performance is like in benchmarking apps such as GFXBench nearer to launch, but although there is a correlation between benchmarking performance and real-world performance, until the final consumer-facing handset hits the market we won't know for sure.
We also don't know how much RAM the OnePlus 5 used for these tests has onboard, as both 4GB and 6GB are rumoured. A 6GB RAM model would have more RAM than both the Pixel series and Galaxy S8 series and it could make a noticable difference to caching apps, graphics, and load speeds.