Brightness and contrast
True to tradition we first take a look at the maximum brightness. Here, the AOC Q2790PQU shows an excellent value of 389 cd/m²; a few qhd-models (green bars, for those of you that did not read the previous page) are even brighter, but this result is more than enough for both home and office use.
The I2490PXQU and the I2790PQU end up considerably lower, the latter remarkably ends up at a mere 245 cd/m² - however this is still sufficient for all but the most brightly lit offices. Especially if this means that the black values are good, we are happy with this result.
Before we take a look at those, we still have to look at the minimum brightness. For all three models it is at about 85 cd/m² and that is fairly bright. In the pitch dark your eyes will probably not like it. We bear in mind that only the most fanatical office slaves will keep working in the pitch dark, meaning this should not matter much for the main target audience.
Looking at the black values at a brightness of white of 150 cd/m², we see that the I2490PXQU and the I2790PQU end up pleasantly high in the graphs, with 0.12 and 0.13 cd/m² respectively. With that it is mainly the black of the 27-inch model that is quite a bit darker when compared with the competitors (aside from the Samsung C27F396FHU with its va-panel). The 24-inch model shows good results as well. The 27-inch wqhd Q2790PQU ends up in the middle of the wqhd-competition.
With maximum brightness the black values are higher, but because of their not too bright backlight the two full hd-models perform relatively well here; the more expensive monitor is not as great, but this is primarily a theoretical test: you will probably not use this monitor at maximum brightness.
The contrast of all three models is good without a doubt. The Q2790PQU does not perform as well as its main competitors, the Iiyama XB2788QS and the Iiyama XUB2792QSU.