The monitor has 90% brightness and 50% contrast by default. I lowered them both to 49% to achieve a 100nit white. The brightness is controlled by means of backlight modulation at a frequency of 215Hz.
The average irregularity of backlight amounts to 16% on black and 14% on white, the respective maximums being 35% and 26%. That’s an acceptable result.
Color gradients are reproduced with banding. Darks merge into black at a contrast of 10% and lower. You should not increase the contrast setting, either. Lights become indistinguishable from white at 55% contrast and higher.
The gamma curves don’t look good at the defaults settings: they differ greatly from the theoretical curve and the blue curve goes apart from the other two. Lowering the contrast setting doesn’t help: the curves retain their shape and position.
The color temperature modes are set up surprisingly well for an inexpensive monitor. The difference between the temperatures of grays is within 300K in the Normal and Reddish modes, which is very good. It is higher at 1000K in the User mode and 3000K in the Bluish mode, making dark halftones bluish. If you prefer warmer colors, the FP91G +U is going to suit you fine. You may want to consider other models if you prefer colder colors.
The color gamut is standard so no commentary is necessary.
The response time average is 11.9 milliseconds with a maximum of 34 milliseconds. This can be counted among best results RTC-less monitors can show, but the FP91G +U can’t stand a comparison with RTC-enabled models.
The contrast ratio and brightness are normal. The low level of black at the 100nit settings can be noted here.
Thus, the BenQ FP91G +U is a low-end 19” monitor with an RTC-less TN matrix. It may be interesting to you if you want an inexpensive monitor with a classic aspect ratio and prefer warm colors. Its color reproduction isn’t exactly accurate and its viewing angles are small as is typical of TN technology. If you don’t want to put up with such drawbacks, you should better consider other models.