V-Ray 2.0 Service Pack 3 was the landmark update that introduced full 64-bit support SketchUp 2015
What is V-Ray?
Graphics: 3D class video card with at least 512MB memory (OpenGL 2.0+ support required). Key Features in V-Ray 2.0 Vray 2.0 For Sketchup 2015 64 Bit
Memory: Minimum 4GB RAM; however, 8GB to 16GB is recommended for stable production environments. V-Ray 2
A revolutionary engine providing instant visual feedback. It allowed users to see lighting and material changes in real-time within the Frame Buffer, utilizing either CPU or GPU power (up to 30x faster with a compatible GPU). V-Ray Proxies: Low (Draft): Quality = 0
Dome Light: Simplified image-based lighting for perfect exteriors.
Here is a comprehensive look at why this specific version was a game-changer and how it functions within the 64-bit environment. The Leap to 64-Bit Architecture