Microsoft has long been rumored to be working on a Surface Phone – and, so hint fresh details reported this weekend, it will be a powerful Windows 10 Mobile handset launching in late 2017.

These details come from “trusted sources” of Nokiapoweruser. That site says that two prototype Surface Phone models are using the beefy Snapdragon 835 processor, which is 30% more area-efficient, 27% better performing and 40% less power-consuming.

These two models are also said to support Quick Charge 4.0 and run a 64-bit version of the Windows 10 Mobile operating system. It’s reported that one model comes with 6GB of RAM and can run X86 apps through Continuum.

The other prototype is said to feature 4GB RAM and lack this same compatibility with X86 apps in Continuum. This has led Nokiapoweruser to speculate that Microsoft could be planning to release a particular Surface Phone for consumers and another aimed at enterprises.

Both phones could have a 5.5-inch QHD display, though the site adds that this is based on guesswork rather than actual measurement of the screens. This suggests that the handsets will be similar in size to Microsoft’s high-end Lumia 950 XL, pictured above, which features a 5.7-inch display.

Sources have told Nokiapoweruser that the Surface Phone will not be launched until late 2017.