Rhino 5.0 x64 can utilize all of your system's RAM, but unoptimized material setups can still cause massive render slowdowns or system crashes. Texture Resolution Rules
Why use optimized materials in Rhino 5? While newer versions of Rhino offer enhanced rendering, V-Ray for Rhino 5 is still a powerhouse. By utilizing high-definition texture maps and physically accurate material properties, you can achieve renders that rival modern real-time engines. Rhinoceros 5.0 x64 VRAY MATERIALS
Mastering Rhinoceros 5.0 x64 V-Ray Materials: A Complete Guide Rhino 5