Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | LG - C5 OLED 77 | Samsung - S90F QD-OLED 65 |
|---|---|---|
| Screen size | 77 " | 65 " |
| Peak brightness | 1300 nits | 1500 nits |
| Dolby Vision | true | false |
| Smart OS | webOS | Tizen |
| Panel type | OLED | QD-OLED |
Between the C5 OLED 77 and S90F QD-OLED 65, the C5 OLED 77 comes out ahead in screen size / dolby vision, while the S90F QD-OLED 65 wins on peak brightness / panel type. Overall, the C5 OLED 77 scores 71.5 and the S90F QD-OLED 65 scores 72.5 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (71.5 vs 72.5). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the C5 OLED 77 if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. The biggest gaps in its favor are screen size, dolby vision, smart os. The single most decisive one: Screen size — 18.46% more. 77 " vs 65 ".
Pick the S90F QD-OLED 65 if you care most about peak brightness / panel type. Its strongest claims are peak brightness, panel type. The single most decisive one: Peak brightness — 15.38% more. 1500 nits vs 1300 nits.
Both ship with comparable refresh rate, hdmi 2.1 ports, vrr, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: LG - C5 OLED 77 or Samsung - S90F QD-OLED 65?
Samsung - S90F QD-OLED 65 leads the current Mars Score by 1.0 points.The more useful decision is the trade-off behind that result: compare screen size, panel type against the way you will actually use the product.
Choose LG - C5 OLED 77 if…
LG - C5 OLED 77 has the measurable edge on screen size in, has dolby vision, smart os.
Choose Samsung - S90F QD-OLED 65 if…
Samsung - S90F QD-OLED 65 has the measurable edge on peak brightness nits, panel type.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why LG - C5 OLED 77 wins
- ▲Screen size — 18.46% more. 77 " vs 65 ".
- ▲Has Dolby Vision.
- ▲Smart OS: webOS (vs Tizen).
Why Samsung - S90F QD-OLED 65 wins
- ▲Peak brightness — 15.38% more. 1500 nits vs 1300 nits.
- ▲Panel type: QD-OLED (vs OLED).
Spec comparison
Display
| Spec | LG - C5 OLED 77 | Samsung - S90F QD-OLED 65 |
|---|---|---|
| Screen size | 77 "lead | 65 " |
| Panel typeⓘ | OLED | QD-OLEDlead |
| Resolutionⓘ | 4K | 4K |
| Refresh rateⓘ | 144 Hz | 144 Hz |
| Peak brightnessⓘ | 1300 nits | 1500 nitslead |
HDR & Smart
| Spec | LG - C5 OLED 77 | Samsung - S90F QD-OLED 65 |
|---|---|---|
| Dolby Visionⓘ | truelead | false |
| HDR10+ⓘ | false | truelead |
| Smart OS | webOSlead | Tizen |
| Dolby Atmosⓘ | true | true |
Gaming
| Spec | LG - C5 OLED 77 | Samsung - S90F QD-OLED 65 |
|---|---|---|
| HDMI 2.1 portsⓘ | 4 | 4 |
| VRRⓘ | true | true |
| ALLM | true | true |
Frequently asked
Which is brighter, C5 OLED 77 or S90F QD-OLED 65?+
S90F QD-OLED 65 peaks at 1500 nits vs 1300 nits.
Which is better for gaming, C5 OLED 77 or S90F QD-OLED 65?+
C5 OLED 77 offers 144Hz refresh and 4 HDMI 2.1 ports.
Does C5 OLED 77 or S90F QD-OLED 65 support Dolby Vision?+
C5 OLED 77 supports Dolby Vision; S90F QD-OLED 65 does not.