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Dell ST2420 review: Dell ST2420

Dell ST2420

Eric Franklin Former Editorial Director
Eric Franklin led the CNET Tech team as Editorial Director. A 20-plus-year industry veteran, Eric began his tech journey testing computers in the CNET Labs. When not at work he can usually be found at the gym, chauffeuring his kids around town, or absorbing every motivational book he can get his hands on.
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Eric Franklin
8 min read

At $239, it's difficult to fault the 24-inch Dell ST2420L too harshly. The monitor includes DVI and HDMI, has a well-designed OSD, and is easy on the eyes. Unfortunately, it earns that low price with unresponsive OSD buttons, difficult-to-reach connections, and uninspiring movie and games performance. Also, although VGA, DVI, and HDMI connections are included, Dell ships the ST2420L with only a VGA cable. Lastly, although most Dell monitors are covered for up to three years, the ST2420L is only covered for a year and costs an extra $50 to get those extra two years of coverage.


Dell ST2420

The Good

The Dell ST2420L has a pleasing aesthetic design and a well-designed OSD, and includes HDMI for a low price.

The Bad

The Dell ST2420L has hard-to-reach connections, its OSD array can be unresponsive, and although the monitor has DVI and HDMI connections, Dell only includes a VGA cable to connect it. Also, it has a low brightness and uninspired games and movie performance.

The Bottom Line

The Dell ST2420L is a decent monitor for its price, but there are other monitors with similar prices that offer much more.

Design and features
The 24-inch Dell ST2420L has a fairly glossy, piano-black chassis, with smooth rounded corners. The bezel is a short 0.75 inches wide on the right and left sides. The panel itself is about 0.6 inches thick initially, and extends back another 1.75 inches to include the ventilation system and connection options, bringing the panel's full depth to 2.35 inches. The bottom of the bezel ends prematurely, revealing about an inch of eye-catching gray that otherwise would not be seen. In the bottom middle of the bezel below the Dell logo is a white LED that illuminates the aforementioned gray, creating a cool look. Unfortunately, the amount of light emitted isn't enough to illuminate the onscreen display (OSD) array in the dark.

The distance between the bottom of the bezel and the desktop is a short 2.25 inches. The circular foot stand is 8 inches in diameter and unfortunately is unable keep the monitor stable if knocked from the sides. And we found the ST2420L was very susceptible to rear force, especially compared with the Samsung PX2370. The monitor is capable of a 10-degree back tilt, but offers no other ergonomic options.

In the middle of the back of the panel is a Dell logo. A few inches below that are the connection options, which consist of HDMI, DVI, and VGA, with no additional connections available, and Dell includes only a VGA cable as the sole cable option. The connections face downward and are tucked up into the chassis in a way that makes them particularly frustrating to access--we prefer it when connections face outward, as on the PX2370, instead of downward. When connections face downward, it usually means you'll need to turn the monitor sideways to connect it or at least get really low in order to see them clearly. The placement of the ST2420L's DVI port is particularly annoying. It's located directly over the foot stand, near the neck of the display, making connection an awkward endeavor.

In the lower right-hand corner, on the face of the bezel, is the OSD array, aligned vertically. In place of buttons, Dell uses touch areas, each denoted by a small gray dot. Touching any of the dots brings up the OSD menu, which pops up parallel to the array, and each option corresponds to one of the four touch areas. Once a new menu comes up, the function of the touch area changes dynamically, as the top two touch areas become the up- and down-arrow buttons used to navigate through the newly seen menu. Since any labels for the OSD are on the screen (other displays typically label them on the bezel), calibrating the display in a dark room should have proven painless. Unfortunately, the lack of a discernable separation between the areas, coupled with lack of illumination and the inconsistent responsiveness of the touch areas, frequently made what is normally a fairly seamless process on other Dell monitors a frustrating chore in this case.

OSD options include the standard brightness, contrast, and various color options. The presets are separated into two categories, Graphics and Video. There are six Graphics presets to choose from: Standard, Multimedia, Game, Warm, Cool, and Custom. Its Video presets are Movie, Game, Sports, and Nature. The presets change the color balance and contrast with the intent of being appropriate to the task at hand. Certain presets also include options to adjust the hue, sharpness, and color saturation. Also, there are additional options for setting the OSD to stay onscreen up to a minute (useful for anyone who will spend a good amount of time calibrating).

Design highlights:
Connectivity: HDMI, DVI, VGA
Ergonomic options: 10-degree back tilt
Resolution: 1,920x1,080
Aspect ratio: 16:9
Audio: Audio In and Out; no speakers
VESA support: No

Feature highlights:
Included video cables? VGA
Backlight: LED
Panel Type: TN
Screen film: Matte
Number of presets: 10
Overdrive: No
Picture options: Brightness, Contrast, Sharpness
Color controls: Hue, Saturation
Gamma control: No
Additional features: Dynamic Contrast mode

DisplayMate performance:
We tested the Dell ST2420L through its DVI input, connected to a Windows Vista PC via a DVI cable from our own bountiful DVI cable stock we've collected over the years. The display posted a composite score of 87 on CNET Labs' DisplayMate-based performance tests, more than a few points lower than the Samsung PX2370's 96. The ST2430L performed well in most of our color and grayscale tests, displaying up to a 253 white level and down to a level 4 dark gray, indicating that the monitor would not oversaturate colors and would be able to display dark detail in movies--both of which we found to be true in our real-world testing.

The monitor did show some very slight color-tracking problems, with a negligible screen push toward green, although this showed up more noticeably when we looked at movies, which you can read more about below. We did see some color compression at the light end of the color scales, particularly in the color red. This indicated that the ST2420L has a lower gamut than the PX2370, which didn't have this problem. Also, thanks to the display's low luminance level, we saw minimal backlight bleed-through on our dark screen test. We also saw some sparse evidence of static ghosting.

In text, we saw no color problems with black text on a white background. Fonts were visible down to a 6.8 size.

We tested the Dell ST2420L in its Movie preset, using the Blu-ray version of "Avatar." The ST2420L displayed the movie with a noticeably drab and "soft," almost blurry look; definitely not as sharp and vibrant as the PX2370 presented the same scenes. Also, faces had a slight green tint. We were able to marginalize the green tint effect by adjusting the hue downward, but this had the unfortunate side effect of pulling much of the red out of the picture as well. As for dark details, we could see most of the intended dark detail of the Na'vi's hair in dark scenes.

Because of our intimate familiarity with World of Warcraft (WoW), it remains the best tool for judging color quality and vibrancy in games. We looked at WoW in the Dell ST2420L's Game preset and found the display delivered an image with colors that were somewhat drab and lacked vibrancy and pop.

Viewing angle:
The optimal viewing angle for a monitor is usually directly in front, about a quarter of the way down from the top of the screen. At this angle, you're viewing the colors and gamma as the manufacturer intended. Most monitors are not made to be viewed at any other angle. Depending on the panel type, picture quality at nonoptimal angles varies. Most monitors use TN panels, which get overly bright or overly dark in parts of the screen when viewed from nonoptimal angles, making for inaccurate color representation. The Dell ST2420L uses a TN panel, and when viewed from the sides or bottom, we perceived the screen to darken about 6 inches off from center; typical for a TN.

Recommended settings and use:
During general use, we found the Standard preset, with the contrast set to 74, to be the ST2420L's optimal picture setting.

Both the Movie and Game presets allow you to adjust the hue and saturation of the display. For movies, we recommend keeping the hue at 50 and adjusting the saturation no higher than 55 and no lower than 50. We recommend the same for games, except the saturation threshold can be as high as 60.

In movies, we weren't able to adjust the Hue to a level that diminished the green tint without also decreasing the amount of red to too great an extent. The green tint problem isn't egregious in any way, but it's noticeable next to the PX2370. Games benefited from the increase in saturation, but still looked drab compared with the PX2370.

As with most TN-based monitors, the Dell ST2420L shouldn't be used if pinpoint-accurate color reproduction is required; the monitor is fine for watching movies, playing games, and for general use, although movies and games are definitely not its strong suit. If you do have stringent color needs, we suggest you narrow your search to IPS- or PVA-based panels only. The more expensive Dell UltraSharp U2711 is a good place to start. The Samsung PX2370 is a great monitor for movies, games, and general use. The Dell ST2420L is best suited for general use and doesn't particularly excel in either games or movies.

Power consumption:
The Dell ST2420 achieved good power consumption, with a Default/On power draw of 19.62 watts, compared with the Samsung PX2370's 25.01 watts in the same test. The consumption delta was higher in our Sleep/Standby test, with the ST2420L drawing 0.62 watts and the PX2370 costing a lower 0.27 watts. With both monitors' center point calibrated to 200 candelas per square meter (cd/M2), the ST2420L drew 23.5 watts, while the PX2370 drew a lower 19.9 watts. Based on our formula, the Dell ST2420L would cost $6.28 per year to run, compared with the Samsung PX2370's $7.65 per year.

Brightness (in cd/m2)
(Longer bars indicate better performance)

(Longer bars indicate better performance)

(Longer bars indicate better performance)

Juice box
Dell ST2420L Picture settings
On (max luminance) 25.7
On (min luminance) 9.06
Sleep 0.62
Calibrated (200 cd/m2) 23.5
Annual power consumption cost $6.28
Score Good

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Service and support
Dell backs the ST2420L with only a one-year limited warranty that covers the backlight. Most Dell monitors are covered for up to three years, making Dell's reduced coverage of the ST2420L disappointing. Dell charges an extra $50 for the extra two years. It also offers support through a 24-7 toll-free number, and 24-7 Web chat. Dell also has a fast 24- to 48-hour e-mail turnaround time--a better package than most monitor vendors, which don't offer weekend support.


Dell ST2420

Score Breakdown

Design 6Features 6Performance 6Support 6