‘Sony XH90 with HDMI 2.1 displays 4k120 out of focus because soc cannot handle it’
Recently it turned out that the Sony XH90, a 4k LCD television, displays images at 4k and 120Hz with a blur, which makes it seem as if there is less sharpness or a lower resolution. There are speculations that this has to do with insufficient computing power at TV’s Mediatek soc.
There is a lot of complaint about this issue on the internet, with Adam Fairclough, an HDR expert, one image posted to show what the display of images in 4k resolution with 120Hz looks like on the Sony XH90. The television displays a test symbol a lot sharper at 4k with 60Hz than the same image at 4k with 120Hz. The problem has not disappeared if a lower resolution such as 1080p with 120Hz is chosen. At 1080p120, significantly less bandwidth is required, but there is also blur, making it unlikely that the problem is entirely related to bandwidth.
The soc as the culprit?
Fairclough thinks that part of the image processing cannot handle the bandwidth required for 120Hz, limiting it to a bandwidth that is within the range of HDMI 2.0 and what the processors can handle, after which it is outputted to the display. He adds that there is likely to be downsampling to 1080p before the data reaches the image processors. He argues that this could be an explanation because the television “has a processor with insufficient power to do 4k120.”
That processor is the MediaTek MT5895-soc. In a video from the HDTVTest website, television reviewer Vincent Teoh reported that all video processing tasks are completely handled by this soc, and that it is not done in conjunction with the X1 video processor. This X1 chip is said to be present in the television according to official specifications, but a forum user speculates that Sony has not incorporated a separate X1 chip in the television and that all software is loaded on the MT5895-soc.
Sony statement
Sony has already responded and confirmed the problem. In another video from HDTVTest, Teoh already noted that compared to 4k60 at 4k120 there seems to be ‘extra image processing’, which he believes leads to ‘a loss of resolution’. He shared these findings with Sony. The company gave him a statement, stating that the observed rendering is intentional, and therefore not a bug.
Sony says 4k120 means that there is a lot of data to be processed, which sometimes leads to a “limitation of the bandwidth.” “In this case, we prioritize 4k120’s ‘smoothness’ because we believe customers expect this smooth rendering.” Sony also says that the difference in clarity is less visible in moving images, so the manufacturer has decided to adjust the signal processing and image quality so that the net results on the screen are such that there is no issue to enjoy 4k120. in any circumstance. Sony says that the issue should not be an obstacle for users who use the XH90 in combination with a PlayStation 5 and are at a normal viewing distance from the television.
Less sharpness at 120Hz
This problem seems to be particularly evident when using a PC monitor and displaying static elements, especially text and symbols. For example, a user reports that the combination of an Nvidia RTX 3090 video card with the Sony XH90 looks very bad at 4k120. “You can scale 4k120 at 200 percent, but that equates to the sharpness of 1080p120 at 100 percent, so that’s pointless. And 1440p120 works, but is only marginally better than 1080p120 and not nearly as sharp as 4k60. 1440p120 also gives additional blur compared to 1440p60. “
There are examples of users who show that the loss of sharpness is also visible in games. Meanwhile, another owner of this television has started a petition to solve the problem. If hardware limitations are actually the cause of the problems, it is obvious that Sony can do little or nothing about the complaints and that, for example, a future firmware update will not offer any relief.
A PS5 television?
The XH90 is an important television for Sony as the device along with the ZH8-8k TV is part of a Sony campaign with the ‘Ready for PlayStation 5’ designation. With this, Sony specifically touts the TVs as suitable televisions for the next-gen gaming experience, in which 4k and 120fps are specifically mentioned. They are the only two TVs from Sony that support this. The XH90 supports HDMI 2.1 and has been on the market since this summer, but only recently the television got the firmware update that actually makes 4k120 possible. Two optional other features of HDMI 2.1, namely allm and vrr, will be available for the XH90 via an update at a later date, according to Sony.