Sony X750D vs X850D vs X700D (XBR65X750D vs XBR65X850D; XBR55X700D vs XBR55X850D)

The X750D (XBR65X750D) and X700D (XBR55X700D) lack the Triluminos Display technology that can be found on the X850D (XBR65X850D; XBR55X850D), which means they don't support a wide color gamut. This is of concern only with HDR content such as 4K Ultra HD Blu-ray discs because they're mastered to the DCI-P3 color gamut (albeit within Rec.2020 container). The Triluminos technology allows the X850D to reach more than 90% coverage of the DCI-P3 gamut, thus better preserving the artistic intent of the director/colorist in comparison to the X750D and X700D which won't be able to display colors they way they are meant to be seen but this only applies to HDR (High Dynamic Range) content. Further, the X750D and X700D feature Precision Color Mapping that optimizes color in order to make the most of their more limited DCI-P3 gamut coverage. It has to be said, however, that the vast majority of content that is available is a standard dynamic range and is mastered to BT.709 color space, which is supported by all three of them, ensuring colors in DVDs, regular Bly-ray discs and broadcast TV are faithfully reproduced but if you desire absolutely accurate colors you might have to calibrate your TV (or have it calibrated by a specialist).

The X750D and X700D have a Direct LED backlight whereas the X850D is an Edge LED. Having the LEDs on the side of the screen allows the X850 to have a slimmer profile in comparison its direct LED counterparts which are thicker due to the fact the LEDs are placed behind the screen. Other than that, the different placement of the LEDs doesn't have any significant impact on the picture quality. The all use IPS type of panels and have wide viewing angles as a result, but the black level is not particularly deep. Considering that the only available form of dimming they are equipped with is frame dimming (instead of the more selective local dimming technology), which means the black level cannot be improved, at least not without making the entire image darker. All of them are HDR compatible but in order to be able to watch HDR content, you'll need to update the firmware of your TV first. Detecting the HDR metadata, however, is one thing, and how it's being reproduced is another. Ideally, your TV also has to be capable of showing brighter highlights and deeper shadows but since neither one of them can selectively boost (or dim) individual LEDs, the peak brightness in HDR mode is approximately the same as in SDR mode, thus you won't be able to see the full impact of HDR.

The X850D and X750D utilize Motionflow XR 960 technology for delivering smooth motion. The panel's native refresh rate is 120Hz on both of them. The X700D, on the other hand, employs Motionflow XR 240, and the panel's native refresh rate is 60Hz. The Motionflow XR is Sony's implementation of motion interpolation, or motion-compensated frame interpolation to be precise. This is a video processing that compares several visual factors on successive frames (such as vertical, horizontal and diagonal motion), and subsequently creates and inserts extra frames between the original ones. While sports can certainly benefit from the extra motion smoothness the X850D and X750D are capable of, film-based content might suffer from the so-called soap-opera effect if you use the Custom Motionflow mode, and have the Smoothness set to Max. You can, however, remove the extra smoothness on the X850D and X750D by adjusting the aforementioned setting to your liking, or using a different Motionflow preset such as Standard, for example. The X700D, on the other hand, cannot reach the same level of motion fluidity due to the lower Motionflow XR 240 index. That being said, the presence of this technology indicates that the X700D is indeed capable of frame interpolation but you also have to consider that the native refresh rate is 60Hz, so the X850D and X750D are slightly better for sports.