A:Answer Hi ManDaddio,
Thank you for your interest in Sony's KD-43X85K! Absolutely, yes. This TV will work with HDMI 2.1 4k@120hz using RTX 3090. For the response rate or input lag, the X85K has 7.2 ms.
With the BRAVIA X85K 4K HDR LED TV, you'll enjoy all of your favorite content. Powered by the 4K HDR Processor X1 and TRILUMINOS PRO, picture quality comes to life with billions of colors and realistic contrast. With Google TV and enhanced Motionflow XR refresh rate technology, your favorite content is easy to find and looks clear and blur-free.
Hope this helps you and thanks again for considering Sony!
- Romeo