Prepar3D vs FSX: what are the differences?
Prepar3D is a Lockheed Martin training and simulation platform developed from the same Microsoft code lineage as FSX. Compared with FSX, modern Prepar3D releases offer 64-bit architecture, newer rendering and far more memory headroom, but require an appropriate licence and version-matched add-ons and can demand stronger hardware.
Prepar3D vs FSX at a glance
FSX remains a 32-bit consumer flight simulator, while Prepar3D has developed into a separate, use-specific simulation platform with substantial technical changes.
| Difference | FSX | Prepar3D |
|---|---|---|
| Purpose | Consumer entertainment, free flight, lessons and missions | Training, education, development and professional simulation under use-specific licences |
| Architecture | 32-bit, including FSX: Steam Edition | Versions 1–3 are 32-bit; version 4 onwards is 64-bit |
| Graphics | DirectX 9, with an optional DirectX 10 Preview mode | Newer DirectX renderers, improved shadows, dynamic lighting and version-dependent features such as PBR materials and enhanced atmospheric rendering |
| Memory | Restricted by a 32-bit address space, making out-of-memory crashes a common problem with dense scenery and complex aircraft | Modern 64-bit versions have much greater memory headroom, although system RAM and graphics memory still impose practical limits |
| Add-ons | Very large, mature library of aircraft, scenery and utilities | Add-ons normally need explicit support for the installed Prepar3D generation |
| Installation model | Add-ons often place files directly in folders such as SimObjects, Gauges, Effects and Scenery | Supports familiar legacy folders but newer releases also use external add-on packages defined through add-on.xml |
| Performance profile | Frequently limited by the main CPU thread | Still sensitive to CPU performance, but newer lighting, shadows and anti-aliasing can place much heavier demands on the GPU |
The Prepar3D version matters as much as the product name. Version 4 introduced the move to 64-bit, while later generations changed the renderer and other subsystems; our breakdown of Prepar3D v4, v5 and v6 explains those generation-specific differences.
Is Prepar3D just an upgraded version of FSX?
No. Prepar3D shares FSX-era technology and terminology, but it is a separate product with its own executable, licence, SDK, configuration files and add-on requirements.
The shared ancestry explains why both simulators use concepts such as BGL scenery, scenery libraries, aircraft.cfg and SimObjects. It does not make their files universally interchangeable. A mistake we see constantly is assuming that a familiar folder structure proves compatibility.
FSX and Prepar3D can be installed on the same PC, but they should retain separate core folders and configurations. Do not install one over the other or point every legacy installer at Prepar3D simply because it accepts a manually selected path.
Are FSX add-ons compatible with Prepar3D?
Some FSX add-ons work in Prepar3D, but compatibility depends on the add-on type, the Prepar3D version and whether the package contains compiled 32-bit code.
- Scenery: Basic BGL scenery and standard textures have the best chance of working. Problems can still appear with airport elevations, autogen, effects, old material definitions and installers that only recognise FSX.
- Simple aircraft: Some models can be adapted, but visual effects, animations, sounds and gauges may fail or display incorrectly.
- Complex aircraft: Treat these as incompatible unless the developer explicitly names your Prepar3D version. They often depend on compiled gauges, external modules and simulator-specific systems code.
- DLL gauges and modules: A 32-bit binary cannot load into 64-bit Prepar3D. Copying the file or changing an installer path cannot fix that; a compatible 64-bit build is required.
- Utilities: Programs using simulator APIs, weather interfaces or traffic hooks may require a dedicated Prepar3D build even when an FSX edition exists.
Check the package description for an exact simulator and major-version match before installing. We separate add-ons tested or supplied for Prepar3D from our much larger FSX aircraft and scenery catalogue because “FSX compatible” alone is not enough for modern Prepar3D.
When an add-on lists both simulators, use its Prepar3D installer or documented package method. Do not copy licensed commercial files between products unless the add-on’s licence permits it.
Does Prepar3D look and perform better than FSX?
A modern Prepar3D release can look substantially better than stock FSX, but it is not automatically faster.
Improved lighting, cockpit shadows, reflections, atmospheric rendering and PBR-capable materials give supported content more visual depth. Older FSX models and textures do not gain all those benefits merely by being loaded into Prepar3D; the aircraft or scenery must use the newer features.
Does 64-bit Prepar3D improve frame rates?
Moving to 64-bit mainly improves memory capacity and stability under heavy add-on loads, not raw frame rate. It removes the tight 32-bit address-space ceiling that causes many FSX out-of-memory crashes, but CPU-heavy traffic or GPU-heavy shadows can still produce poor performance.
Prepar3D settings such as dynamic lighting, shadow casting, anti-aliasing, autogen and AI traffic can cost more performance than their rough FSX equivalents. Excessive graphics settings can also exhaust video memory, causing severe stutters or graphics-device errors even when plenty of system RAM remains.
Which should you choose: Prepar3D or FSX?
Choose according to your intended use, essential add-ons and hardware rather than assuming that the newer platform will always be the better fit.
- Choose FSX when you want a consumer entertainment simulator, depend on an extensive collection of FSX-only add-ons, or use hardware better suited to its older graphics workload.
- Choose Prepar3D when your use complies with its licence terms and you need a 64-bit training platform, newer rendering features or aircraft and scenery explicitly developed for your Prepar3D version.
- Let critical add-ons decide when a particular aircraft, cockpit, instructor station or scenery package is essential. Confirm support for the exact simulator release before buying or migrating.
The practical difference is this: FSX offers maximum access to legacy content, while 64-bit Prepar3D provides more memory headroom and newer simulation technology at the cost of stricter licensing, higher hardware demands and more fragmented add-on compatibility.