It all depends on what your feeding your device. If the input signal comes from a cable box then, you can't control action smoothing if you have it anyway. Unless your cable provider is pushing 4K through it fiber, your getting HD quality at best and they control every aspect of the feed. What you my be attempting to do on your end is superficial. However, If for instance you have a quality 4K DVD and the TV does not support action smoothing then perhaps your DVD does and you can achieve the same effect. I say this only because if you own the latter then this TV is still worth the buy. Remember, every component you purchase doesn't have to be 4K to achieve 4K results because they could cancel each other out. The real source of achieving a quality view rests in the cabling such as the HDMI cable between the two devices. The HMDI cable must be rated for 4K. I went a little off the path but I hope that helps!
Please note: I have no preference on the brand of DVD player, the attached is purely just a recommendation only. I do not own this brand or model and can't comment on it's features or functions.
Insignia™ - 6' 4K Ultra HD HDMI Cable - White
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Samsung - UBD-M9500 Streaming 4K Ultra HD Wi-Fi Built-In Blu-Ray Player - Black Titanum
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