Hi Jimbo - Good question. Processing & Picture: The S90F adds the NQ4 AI Gen3 Processor for faster, smarter upscaling and Color Booster Pro, enhancing color vibrancy and accuracy. Motion: Both models offer excellent motion handling (up to 144Hz for PCs), but the S90F adds AI Auto Game Mode for smarter, scene-based game optimizations. Audio: Audio features are similar, with the same solid 2.1 channel (20W for 42", 40W for 48") system with Dolby Atmos, OTS Lite, Q-Symphony, Adaptive Sound Pro, and Active Voice Amplifier (AVA) Pro. Design: No major design changes – both TVs share the same sleek LaserSlim profile. Smart: S90F steps up with Samsung Vision AI, adding personalized recommendations, real-time translation, gesture controls, and new smart lifestyle features.
~ Samsung Specialist