Well I'm not a tech guy but yes, it can take much more advantage of your RAM and GPU than a 32 bits platform, much more optimized for modern computers with a good CPU as well. Two things I noted is that is much more smooth, and the texture rendering radius is way better with no blurries as I had even in V3. You can see much, much more detail now and farther away.
You still need a good computer and spend good money in some "essential" addons as a weather engine or a good landclass but well worth the investment.
A list of V4 new features:
""General Platform Updates
64-bit simulation architecture
Unicode compatible
Modernized User Interface (UI) design for quick navigation and customization
Updated native virtual reality (VR) support for Oculus Rift and HTC Vive
Updated vector data (coastlines, lakes, rivers, roads, rails, parks, streams and utility lines) for:
Africa
Middle East (Israel, Turkey, Syria, Lebanon, Iran, Iraq, Afghanistan, Pakistan, Saudi Arabia, and more)
Southeast Europe (Greece, Albania, Macedonia, Bulgaria, Romania, Black Sea, and more)
Southeast Asia (Indonesia, Philippines, Vietnam, Cambodia, Laos, Thailand, Myanmar, Papua New Guinea, Solomon Islands, and more)
Updated custom 3D model placement in Athens, Egypt, Israel, Dubai and Hong Kong
Hundreds of new updated generic 3D model buildings in Tel Aviv and Hong Kong
Updated Shuttle Radar Topography Mission (SRTM) 90m digital elevation for Southeast Asia and Middle East regions
Updated native mission gauges to Scaleform
Views and panels can now be docked into any undocked view
Updated multiplayer voice chat codec – higher quality chat audio
Expanded ribbon drawing capabilities in the Navigation Visuals screen including drawing based on vehicle type and the ability to change color per category
Added video recording capability. Can be assigned to a key event in the UI.
Control Tower can now be selected in the Select Airport screen
Custom cameras can now be saved on a scenario or global level
Material temperatures – IR sensor views now react accordingly
3D trees (SpeedTree) integrated into autogen system. This feature can be toggled on and off in the UI under Options – World (Dynamic 3D Autogen Vegetation).
New 3D rain/snow system. This feature can be toggled on and off in the UI under Options – Weather (Detailed Precipitation).
Dynamic lighting support
Support for local SpeedTree wind effects
Support for higher resolution ground textures
Autogen visibility range can now be configured
Updated various textures including runways, taxiways, hangars, and terminals
Added SceneryLodOrigin and TerrainLodOrigin fields to camera definitions preventing terrain paging issues when switching between certain views.""
http://www.prepar3d.com/news/2017/05/114192/