For the purpose of this review, I didn't use any calibration tools at first, since most end-users don't have any these available. I took the monitor out of the box, and prepped the tests uncalibrated. Then, I went on, calibrated it, and took the measurements again again.
S277HKwmidpp was hooked up to a machine with a Sapphire AMD R9 280X running the 15.7.1 Catalyst Driver.
Whilst my monitor testing experience is limited, I used the i1 Display Pro and X-Rite i1 Pro, and used 'em alongside SpectraCal's CalMan 5.201 software package for some added results regarding image quality
There are various uniformity tests (white, neutral shades, black). For the purpose of this review, I tested the luminance uniformity. First, I set the screen center at a luminance of 220cd/m2, and then took 8 readings from the surrounding regions. The end-results is a 15.32% variation from the center, in the bottom-left corner.
The variation is higher than most TN-panel monitors I checked in the past year, and it's even slightly noticeable to the naked eye. It seems IPS panels still struggle with image uniformity, despite the massive progress they made in the past recent years.
Uncalibrated, the S277HK delivers an impressive 99% color coverage in sRGB mode, 82% Adobe coverage and a deltaE of 3.11. Once calibrated and profiled at a brightness of 180cd / m2, color accuracy has dramatically improved to an average deltaE of 1.56, which is one of the best values I've seen in the past year.
Out of the box, S277HK comes with 6950K white-point, warmer than the desired 6500K.
With a native white-points measuring 306cd / m2 at maximum, this is slightly over the manufacturers specifiec 300cd /m2. The contrast ratio is rated at 1000: 1, however during my tests the results suggested a 570:1, uncalibrated, at 100% brightness. After calibration, the average was around 758:1, which is a dramatic improvement, though still off from the specified figure.
IPS panels are known for their large viewing angles, and the results are no different for the S277HK, where even at extreme viewing angles, the color reproduction remains stable. Some loss of brightness and contrast might be noticed (over 170 degrees), but other than that, there are no differences.
Here's the thing, being a 4K monitor, in most situations, the power-consumption figure is always going to be higher than most 1080p or 1440p options out there. In idle, S277Hk consumes 3W, which is not really a high enough number. However at 100% brightness, the monitor could eat-up as much as 55W, a higher figure for sure, but not an unexpected one.