The minimum specification for 90hz play is a GTX 965m, but comparing that to the Rift or Vive is like comparing apples to oranges because you don't know what that means... I mean the GTX 965m has about half the rendering hourse power of the GTX 970, the minimum spec for the Rift... But what will it run? The GTX 965m is equivalent to a GTX 750ti and that can run ED, so does that mean the GTX 970 will run better on ED than the Rift? I've no idea.
Hopefully this will clear it up a little for you.
Windows Mixed Reality (WMR) is an application built into Windows 10 build 1703, it allows WMR compatible devices (hololens and the devices you are interested in) to run Windows 10 (kind of) in a VR or AR enviroment. This allows you to run standard windows apps from a virtual screen within those devices or run specifically created WMR apps in VR or AR (depending on which they were built for). It also allows you to pin shortcuts to the walls of the WMR environment, or anywhere in space when used in AR mode.
https://www.youtube.com/watch?v=7CXdQWFMcRk
As you can see, it is very basic (graphically speaking). I spent some time with it on a Hololens - it was pretty rubbish in my opinion but may be better when used in VR as imo the Hololens was pretty poor also.
The minimum spec to run the base 'Windows Mixed Reality' app on these devices @ 90Hz is a GTX 965m - Some WMR apps will have higher minimum specs than the base spec to run WMR itself - just like how some apps on the MS Store have higher minimum specs than Windows 10 itself.
The minimum spec to actually run SteamVR (required to run Elite in VR on these devices) will remain the same as the published SteamVR minimum specs. Oculus do not plan on supporting these devices via their runtime (at least for the time being). You should be able to test your rig using the SteamVR performance app to see if it's a VR ready machine.
A GTX 965m may very well run WMR but a GTX 965m will always struggle to run even the most basic SteamVR game (if it could at all - which I doubt). A GTX 970 should run both the Rift and SteamVR, however a GTX970 would struggle to maintain 90FPS in Elite on a VR device.
Due to ASW and it being exlcusive to Oculus, the Rift will always run a game such as Elite smoother than any other VR HMD via SteamVR (HTC Vive included). This may change if / when Valves ASR catch up.
The video link here should give you an idea of what ASW does and how it compares to SteamVRs ASR. In short ASW is what you want if you have a weaker GPU and / or CPU.
https://www.reddit.com/r/oculus/comments/6z7b6a/asw_atw_oculus_vs_reprojection_valve/