The Alienware AW2521HF has an exceptionally low input lag of only ~2ms, which guarantees that you won’t be able to notice or feel any delays between your actions and the result on the screen. There’s also the Dell Alienware AW2521HFL model with a different color scheme (‘L’ stands for ‘Lunar Light’ whereas the AW2521HF model has the ‘Dark Side of the Moon’ theme). Now, the specified response time speed is 1ms (GtG – gray to gray pixel transition) when using the ‘Extreme’ overdrive mode, 2ms with ‘Super Fast,’ and 4ms with ‘Fast.’ The variable refresh rate range is 48-240Hz, but LFC (Low Framerate Compensation) is supported meaning that below 48FPS, the refresh rate will be multiplied (for instance, 47FPS x 5 -> 235Hz) for smoother performance.

In some rare cases, dark pixels may not quite change into brighter shades in time with the refresh rate, which can result in visible ghosting behind fast-moving objects when dark pixels are predominant in the picture (dark scenes). Input lag is where the Alienware 25 really shines, as it should in a gaming monitor. Using an HDFury Diva HDMI matrix, we measured a 4.1-millisecond input lag on a 60Hz signal, which means an input lag of just over 1ms at 240Hz. That makes the Alienware 25 the fastest gaming monitor we’ve tested to date.Next, in the Nvidia control panel, under the "Display" option on the left, in "Adjust desktop color settings", I set the color channel to "All Channels", increased the Brightness to 72%, lowered the contrast to 25%, and lowered the Gamma to .96. Digital vibrance and Hue were left alone. I've been reading that the best Gamma options are between 1.8 and 2.2 for computer monitors but I couldn't raise the Gamma in the nvidia control panel that high because the entire monitor would appear insanely washed out and no other combo of settings could get rid of that effect. I also used the windows color management tool and the below linked tool while tweaking the settings. My current Brightness setting on the monitors display settings is 90% and the contrast is set to 96%. The average contrast ratio with only brightness adjusted was 1054:1, a hair above the specified 1000:1 and as expected for the panel. With our ‘Test Settings’ we recorded a perfectly respectable 1063:1. The highest contrast ratio recorded on the table was 1107:1, using ‘Custom Color’ with all colour channels at their neutral position of ‘100’. The lowest contrast ratio recorded was 831:1, following the significant adjustments made for our ‘Relaxing evening viewing’ settings. The maximum luminance recorded in this table was 427 cd/m², whilst the minimum white luminance recorded was 33 cd/m². This yielded a 394 cd/m² luminance adjustment range with a good bright maximum and dim minimum. The image below is a macro photograph taken on Notepad with ClearType disabled. The letters ‘PCM’ are typed out to help highlight any potential text rendering issues related to unusual subpixel structure, whilst the white space more clearly shows the actual subpixel layout alongside a rough indication of screen surface. This model uses a ‘regular’ (medium) matte anti-glare surface. Strong glare-handling is provided due to significant diffusion of ambient light. This diffusion also affects light emitted from the monitor, with a negative impact on the clarity and vibrancy potential of the screen. The screen surface has a bit of graininess to it when observing lighter shades, a very slightly ‘sandy’ look to it, if you like. It doesn’t show strong graininess or a heavily smeared appearance, however. The surface texture is quite similar if not a touch lighter than the surface texture used on most high refresh rate ~24” Full HD TN models.

The monitor produced most shades here quite faithfully, accounting for the natural differences related to emissive vs. non-emissive objects noted above. Some shades appear a touch oversaturated due primarily to the slight extension in the gamut, the most noticeable being dark lime green (18) which appeared a touch more ‘neon’. On models with a significantly wider gamut, this shade and candy apple red (14), to name but a few, tend to look significantly more ‘neon’ than they appear here. Candy apple red appeared with a bit of an orange-red tone due to extension in the red to green edge of the gamut. Some shades, such as cerulean (2) and lilac (8), appear somewhat undersaturated. Gamboge (23) verged too much on a mustard yellow without a suitably warm golden hue, too. Medium orange (3), Persian pink (6) and looked slightly undersaturated in person, but they appear much less saturated and overly bright in the image compared to how they actually looked on the monitor. The consistency is also very good in most cases, superior to VA models and far superior to TN models (references here). Aquamarine (4) is particularly good at highlighting this relative strength. Medium chocolate brown (24) is also good for highlighting colour consistency, which like Aquamarine is positioned at the extremities of the screen. Medium chocolate brown and some neighbouring shades appear a touch more saturated and warmer in tone on the AW2521HF when displayed at the bottom vs. top of the screen. But this is due more to uniformity on our sample than viewing angle behaviour. Although this won’t correct uniformity issues, profiling the monitor with your own colorimeter or spectrophotometer is always advised for best results if the strongest colour accuracy is desired. A sensitive camera and a utility called SMTT 2.0 was used assess the latency of the Dell Alienware AW2521HF. Over 30 repeat readings were taken to help maximise accuracy. Using this method, we calculated 2.63ms (under 2/3rds of a frame at 240Hz) of input lag. At 60Hz we measured a slightly higher but still reasonable 6.47ms. This figure is influenced both by the element of input lag you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). It indicates a very low signal delay at 240Hz which even sensitive users shouldn’t find bothersome. Note that we have no way to accurately measure input lag with Adaptive-Sync active in a variable refresh rate and frame rate environment. Note that there is always some disparity between how emissive objects (monitor) and non-emissive objects (printed sheet) appear. The representation of shades in this image depends on the camera and your own screen, it’s not designed to show exactly how the shades appear in person. It still helps demonstrate some of the relative differences between the original intended sRGB shade and what the monitor outputs, however. Full profiling and appropriate colour management on the application would provide a tighter match, our intention here is to show what can be expected in a non colour-managed environment. Should you want to dispense with the stand and use your own (or wall mount it) that’s possible, too, since the screen has VESA standard 100mm mounting points but it would be a shame to miss out on such a stylish stand.To test the performance of monitors, I run a DisplayCal verification using an X-Rite i1Display Pro colorimeter, alongside a few by-eye tests using Lagom's LCD test patterns. The AW2521H is not an HDR or wide gamut monitor, instead hitting about 450 nits of maximum brightness and covering 92.8% of the sRGB color space. It is, however, extremely accurate within that sRGB space. As it’s the case with most Alienware gaming monitors, the design has a sci-fi vibe with a premium build quality and the AlienFX RGB lighting technology with plenty of customization. An obvious cool (blue) almost icy-looking tint due to very high colour temperature. Some shades brightened up just slightly due to gamma handling, but not by a huge amount. Strong consistency due to IPS-type panel, without the perceived gamma and saturation shifts associated with TN or VA panels. In case you just want to run your monitor at a fixed 240Hz refresh rate or with FreeSync/G-SYNC, the Dell AW2521HF will do just fine!