Iiyama  - Iiyama G-Master GB2788HS


Iiyama G-Master GB2788HS: a 27-inch FreeSync 144 Hz monitor!

Aprox. 407€

See specifications

Here is a model for players that we have been impatiently waiting for: a 27 inch Full HD monitor with a refresh rate of 144 Hz and FreeSync / AdaptiveSync compatible to bring even more fluidity.

Positive points

Very good reactivity (4.5 ms).

Refresh rate at 144 Hz!

FreeSync compatible.

Good rendering after calibration.

Height adjustable foot.

Bad points

No USB hub.

Limited definition in office automation.

Contrast ratio.

Viewing angles.

Our review


The Iiyama G-Master GB2788HS monitor has a 27-inch TN panel with a Full HD definition of 1920 x 1080 px. It stands out from the competition by a refresh frequency of 144 Hz and its compatibility with AMD's FreeSync, adopted by VESA as an optional standard for DisplayPort 1.2a under the name AdaptiveSync. Sold around 400 €, it targets players above all because of its relatively limited definition, but appreciable in games since it can display more images per second than Quad HD.


The chassis of the Iiyama G-Master GB2788HS is a classic of the Japanese company. The matt black plastic is of good quality, while the 27-inch TN panel has a matt coating that filters out almost all of the reflections. Unlike the ProLite B2783QSU, the screen edges are quite wide.

[/ link] Height adjustment of the foot on 13 cm

The foot is adjustable in height by 13 cm, tilted by + 17 ° and rotated 45 ° to the right and left at the base. It lacks only a pivot for the transition to portrait orientation, which is not recommended with TN panels anyway, whose vertical viewing angles are very limited.

Connectivity focuses on the essentials: an HDMI 1.4 input, a DisplayPort input and a DVI. At the audio level, the monitor offers an output and an input in 3.5 mm jack format. The two 2.5-watt speakers produce unpretentious, low-bass and treble sound. We note the absence of a USB hub.

Four touch buttons allow access to the settings for contrast, brightness, overdrive, dynamic contrast, black level, X-Res (image sharpness), temperature, reduction of blue light and FreeSync. It is however impossible to modify the gamma.

By lowering the brightness to 42 to obtain a white at 150 cd / m², the Iiyama G-Master GB2788HS monitor consumes 26 watts, a relative consumption of 129 W / m², much higher than the average of monitors (100 W / m²). On this point, this monitor is greedy and it will cost you around € 8 per year 8 hours a day, 5 days a week.

Colors and contrast

Default: average gray temperature: 6,750 K

Default: gamma curve at 2.0

Default: Average Delta E at 4.0

Out of the box, this monitor is not free from defects with slightly burnt whites and an average gamma which logically stands at 2. The average temperature of 6,750 K is good, always better than the average delta E, measured at 4.

Manual adjustment: average gray temperature: 6,630 K

Manual adjustment: gamma curve at 2.1

Manual adjustment: Delta E medium at 3.9

Manual settings are relatively limited since it is impossible to play on the gamma. Here, we set the temperature to Normal to approach 6,500 K and we lowered the brightness to 42 to obtain a white at 150 cd / m². The average temperature then drops to 6,630 K and the gamma rises slightly to an average of 2.1, but always with overexposed whites. These adjustments do not allow perfect colors to be displayed, even if the average of Delta E is imperceptibly (3.9).

Calibrated: average gray temperature: 6.840 K

Calibrated: gamma curve at 2.2

Calibrated: Delta E medium at 3.5

Calibration with the probe stabilizes the temperature and gamma curves. The slightly high temperature (6,840 K) results in a very slightly cold rendering then, while the gamma is perfect on all gray levels. The calibration probe does not work miracles in color and the delta E remains greater than 3, but still drops to 3.5. The color profile is available on Focus Numérique.

The contrast of 970: 1 is good for a TN panel, but it cannot compete with that of the best VA monitors which exceeds 3,000: 1, in particular the Eizo Fortis FG2421.

We noted an average difference in white homogeneity of only 4% over the entire TN panel. Unfortunately, this good homogeneity is sealed by the reduced angles of the TN panel, in particular the vertical angles which reveal a gradient when a uniform sun is displayed. We did not find any light leaks or clouding.


This Iiyama monitor uses Pulse Width Modulation (PWM) to manage the LEDs of the backlight system. This brightness adjustment technology varies the intensity of the LEDs permanently and can cause eye fatigue and headaches for people who are too sensitive to them.

In terms of responsiveness, it's a no-fault for the Iiyama G-Master GB2788HS. The afterglow time measured at 4.5 ms is quite simply one of the best readings in the laboratory. This time is obtained with the Overdrive set to +1. Changing to the higher value (+2) results in a reverse ghosting effect on a black background. This extraordinary responsiveness allows the screen to actually display 144 images per second.

We measured the display delay of only 9.8 ms, again one of the best times recorded on a monitor. There is thus no lag between the action and its repercussion on the screen. This screen will therefore be suitable for professional players and therefore all others.


Less versatile than the Iiyama ProLite B2783QSU, the G-Master GB2788HS is an excellent monitor for gaming. Its unrivaled responsiveness, high refresh rate and FreeSync compatibility are not unrelated to this and allow you to enjoy a smooth experience. in any circumstance. The lack of contrast and the reduced viewing angles remain two weaknesses inherent in TN technology.