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Dell S2725DS vs LG UltraFine 40U990A-W

Side-by-side comparison of viewing distance, PPI, and specifications

Dell S2725DS

27" · 2560×1440 · IPS
Optimal Viewing Distance 80cm
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LG UltraFine 40U990A-W

39.7" · 5120×2160 · IPS
Optimal Viewing Distance 62cm
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Category Ranking

Pixel Density (PPI)67in category
Dell S2725DS109 PPI #55
LG UltraFine 40U990A-W140 PPI #30
93 PPI224 PPI
HDR Peak Brightness67in category
Dell S2725DS350 nits #61
LG UltraFine 40U990A-W600 nits #22
250 nits2000 nits
DCI-P3 Color Gamut63in category
Dell S2725DS79% #63
LG UltraFine 40U990A-W99% #2
79%100%
Refresh Rate
Dell S2725DS100 Hz
LG UltraFine 40U990A-W120 Hz
StandardHighUltra

Summary

  • Sharpness: advantage LG UltraFine 40U990A-W — At 65cm, the LG UltraFine 40U990A-W is retina (140 PPI) while the Dell S2725DS is not — you need to sit at least 80cm away for pixel-free viewing.
  • Brightness: advantage LG UltraFine 40U990A-W — The LG UltraFine 40U990A-W is 29% brighter in SDR (450 vs 350 nits), a noticeable difference for outdoor readability. HDR peak: 600 vs 350 nits.

Key Differences

Specification Dell S2725DS LG UltraFine 40U990A-W
Response Time 4 ms GTG 5 ms GTG
Screen Size 27" 39.7"
Resolution 2560×1440 5120×2160
Pixel Density (PPI) 109 140
Optimal Viewing Distance 80cm 62cm
Refresh Rate 100 Hz 120 Hz
SDR Brightness 350 nits 450 nits
HDR Peak Brightness 350 nits 600 nits
Contrast Ratio 1:1,500 1:2,000
Color Gamut sRGB 99% · DCI-P3 79% sRGB 100% · DCI-P3 99%
Year 2024 2025
All specifications
Specification Dell S2725DS 2024 LG UltraFine 40U990A-W 2025
Screen Size 27" 39.7" (Better)
Resolution 2560×1440 5120×2160 (Better)
Pixel Density (PPI) 109 140 (Better)
Optimal Viewing Distance 80cm 62cm (Better)
Panel Type IPS IPS
Viewing Angle 178° 178°
Aspect Ratio 16:9 21:9
Refresh Rate 100 Hz 120 Hz (Better)
Variable Refresh Rate (VRR) FreeSync FreeSync Premium
Response Time 4 ms GTG (Better) 5 ms GTG
HDR Certification None DisplayHDR 600
SDR Brightness 350 nits 450 nits (Better)
HDR Peak Brightness 350 nits 600 nits (Better)
Contrast Ratio 1:1,500 1:2,000 (Better)
Ports 2x HDMI · 1x DP 2x HDMI · 1x DP · USB-C · USB Hub
Color Gamut sRGB 99% · DCI-P3 79% sRGB 100% · DCI-P3 99% (Better)
Year 2024 2025 (Better)

Frequently Asked Questions

Which has better PPI: Dell S2725DS or LG UltraFine 40U990A-W?
The LG UltraFine 40U990A-W has 140 PPI compared to 109 PPI for the Dell S2725DS.
Which has a closer optimal viewing distance?
The LG UltraFine 40U990A-W requires 62cm vs 80cm for the Dell S2725DS to reach retina quality.
Methodology & Sources

Formula: Retina distance (cm) = 3438 / PPI. Displayed values are rounded for readability.

Sources: Official manufacturer spec sheets and product pages. Specs are normalized before comparisons.

Comparison winners are calculated metric by metric (higher is better for most specs; lower is better for distance/response time).

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