This is all new to me but I did find this as a reference:
Which use cases are best suited for iray?
• Architectural Visualization
• Lighting Design Visualization
• Automotive Styling and Marketing Visualization
• Engineering and CAD (Styling & Design)
• Engineering and CAD ( Lighting Simulation)
• Product Design Visualization
• Sales and Marketing Content Creation
Which use cases are best suited for mental ray?
• Feature film animation
• Broadcast motion graphics
• TV and feature film visual effects
• Animated marketing and promotional media It's an Autodesk document
It might be worth a try to use iRay but according to the document link, iRay is not well suited for animation. My interest is primarily game design so I'm thinking I may not invest in the NVidia GPUs.