The specs for the Acer K335 list a 10,000:1 contrast ratio, which if true would made it would have outstanding performance for this class of projector. However, in our evaluation it was immediately apparent that the contrast ratio was far lower than the Acer specification. After verifying the projector's brightness and contrast controls were set to produce the correct reference white and black levels the contrast ratio measured less than 1000:1. When viewing video on the K335 in 'Movie' mode, dark scenes appeared rather flat due to the relatively low contrast and shadow details faded into a grey background. These concerns are not a real issue when using the K335 for business presentations but illustrate one reason why the K335 would not be good choice for watching TV and movies at home.
The Acer K335’s LED light source runs cooler than traditional lamp-based projectors and the reduced heat generation allows the two small fans that create air flow through the projector to run relatively quietly. Acer does not provide a dB rating, but it produces a modest noise level in normal operation, but in 'Bright' mode the fan noise increases noticeably. Subjectively, the projector is relatively quiet for its small size and the built-in three watt speaker is able to overcome the fan noise.
Pocket and Pico projectors are becoming popular for use by video gamers. I checked the input lag on the Acer K335 by connecting the HDMI output from my laptop to the K335's HDMI input and also with the VGA (analog) output of my laptop connected to the VGA input of a desktop monitor. This, and similar tests, actually provide the different in input lag between the connected monitor and the connected projector. This test does yield useful results since the desktop monitor, when using its VGA input, is expected to have a relatively small input lag of only few milliseconds. I tested the Acer K335 in both its 'Bright' mode and in its 'Game' mode and measured similar maximum input lag times in both modes. The maximum input lag observed was 32 milliseconds.