As was reported, the Steam Deck OLED comes with SteamOS 3.5 preinstalled, while the stable channel is still on 3.4.
This means if reviewers didn’t take care to properly match the software versions on the OLED and LCD models, they might not compare apples to apples. The effect is probably small, but so is the reported performance and power draw difference between the models. Also SteamOS 3.5 introduces the saturation slider which in its default setting tries to emulate sRGB more, and could affect screen comparisons.
See for example Taki Udon’s first video, where clearly it is visible that MangoHUD is an older version on the LCD model https://youtu.be/3C6ekDyO18s?t=807
So unless it is explicitly mentioned or shown otherwise, assume that part of the differences might be due to different software versions.
I found this to explain it:
https://youtu.be/Oy3cKwq6vEw
Pixel color change response time on OLED is faster. 30x faster.
On the LCD, this creates a motion blur effect. We can see the slow motion comparison near the beginning of above video.
For some people, the much faster OLED pixel response time can make stuttering visuals at lower FPS. <– this is what I found when googling.
Alternately, people can see smearing and ghosting at higher FPS on LCDs, when compared to OLED.
The smearing on LCD is especially noticeable in dark areas in a game, that is the pixel response time is slowest between black pixels and bright pixels.
Overall, TBD.
I’m going to wait and see what people say about steam deck OLED running at 40Hz or 30FPS @ 60Hz.