LG UltraFine 40U990A-W vs Samsung ViewFinity S9 5K
Side-by-side comparison of viewing distance, PPI, and specifications
Category Ranking
Pixel Density (PPI)67in category
LG UltraFine 40U990A-W140 PPI #30
Samsung ViewFinity S9 5K218 PPI #5
93 PPI224 PPI
HDR Peak Brightness67in category
LG UltraFine 40U990A-W600 nits #22
Samsung ViewFinity S9 5K600 nits #22
250 nits2000 nits
DCI-P3 Color Gamut63in category
LG UltraFine 40U990A-W99% #2
Samsung ViewFinity S9 5K99% #2
79%100%
Refresh Rate
LG UltraFine 40U990A-W120 Hz
Samsung ViewFinity S9 5K60 Hz
StandardHighUltra
Summary
- Sharpness: no visible difference — Both screens exceed the retina threshold at 65cm. The Samsung ViewFinity S9 5K has 36% higher pixel density (218 vs 140 PPI), but this only becomes visible below 40cm.
- Brightness: advantage Samsung ViewFinity S9 5K — The Samsung ViewFinity S9 5K is 33% brighter in SDR (600 vs 450 nits), a noticeable difference for outdoor readability. HDR peak: 600 vs 600 nits.
Key Differences
| Specification | LG UltraFine 40U990A-W | Samsung ViewFinity S9 5K |
|---|---|---|
| Screen Size | 39.7" | 27" |
| Refresh Rate | 120 Hz | 60 Hz |
| Contrast Ratio | 1:2,000 | 1:1,000 |
| Color Gamut | sRGB 100% · DCI-P3 99% | sRGB 100% · DCI-P3 99% · Adobe RGB 94% |
| Year | 2025 | 2023 |
| Resolution | 5120×2160 | 5120×2880 |
| Pixel Density (PPI) | 140 | 218 |
| Optimal Viewing Distance | 62cm | 40cm |
| SDR Brightness | 450 nits | 600 nits |
All specifications
| Specification | LG UltraFine 40U990A-W 2025 | Samsung ViewFinity S9 5K 2023 |
|---|---|---|
| Screen Size | 39.7" (Better) | 27" |
| Resolution | 5120×2160 | 5120×2880 (Better) |
| Pixel Density (PPI) | 140 | 218 (Better) |
| Optimal Viewing Distance | 62cm | 40cm (Better) |
| Panel Type | IPS | IPS |
| Viewing Angle | 178° | 178° |
| Aspect Ratio | 21:9 | 16:9 |
| Refresh Rate | 120 Hz (Better) | 60 Hz |
| Variable Refresh Rate (VRR) | FreeSync Premium | None |
| Response Time | 5 ms GTG | 5 ms GTG |
| HDR Certification | DisplayHDR 600 | None |
| SDR Brightness | 450 nits | 600 nits (Better) |
| HDR Peak Brightness | 600 nits | 600 nits |
| Contrast Ratio | 1:2,000 (Better) | 1:1,000 |
| Ports | 2x HDMI · 1x DP · USB-C · USB Hub | 1x DP · USB-C · USB Hub |
| USB-C Power Delivery | — | 90 W |
| Color Gamut | sRGB 100% · DCI-P3 99% (Better) | sRGB 100% · DCI-P3 99% · Adobe RGB 94% |
| Year | 2025 (Better) | 2023 |
Frequently Asked Questions
Which has better PPI: LG UltraFine 40U990A-W or Samsung ViewFinity S9 5K?
The Samsung ViewFinity S9 5K has 218 PPI compared to 140 PPI for the LG UltraFine 40U990A-W.
Which has a closer optimal viewing distance?
The Samsung ViewFinity S9 5K requires 40cm vs 62cm for the LG UltraFine 40U990A-W to reach retina quality.
Related Comparisons
Alienware AW2725DF 27" 2024 · 110 PPI · 26.7" · 360 Hz
vs LG UltraFine 40U990A-W 2025 · 140 PPI · 39.7" · 120 Hz
Alienware AW2725DF 27" 2024 · 110 PPI · 26.7" · 360 Hz
vs Samsung ViewFinity S9 5K 2023 · 218 PPI · 27" · 60 Hz
Alienware AW3225QF 32" 2024 · 139 PPI · 31.6" · 240 Hz
vs LG UltraFine 40U990A-W 2025 · 140 PPI · 39.7" · 120 Hz
Alienware AW3225QF 32" 2024 · 139 PPI · 31.6" · 240 Hz
vs Samsung ViewFinity S9 5K 2023 · 218 PPI · 27" · 60 Hz
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).
Last updated: