Between the C5 OLED 77 and QM851 Mini LED 75, the C5 OLED 77 comes out ahead in screen size and hdmi 2.1 ports, while the QM851 Mini LED 75 wins on peak brightness and smart os. Overall, the C5 OLED 77 scores 66.9 and the QM851 Mini LED 75 scores 79.6 on our Mars Score.
Which should you buy?
The QM851 Mini LED 75 is the clear pick on raw spec strength, leading by 12.7 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
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, hdmi 2.1 ports, panel type.
Pick the QM851 Mini LED 75 if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. Its strongest claims are peak brightness, smart os.
Both ship with comparable refresh rate, dolby vision, vrr, so those specs don't separate the two — focus on the differences below.
Bottom line: the QM851 Mini LED 75 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why LG - C5 OLED 77 wins
- ▲Screen size — 2.67% more. 77 " vs 75 ".
- ▲HDMI 2.1 ports — 2.00 more. 4 vs 2.
- ▲Panel type: OLED (vs Mini-LED).
Why TCL - QM851 Mini LED 75 wins
- ▲Peak brightness — 284.62% more. 5000 nits vs 1300 nits.
- ▲Smart OS: Google TV (vs webOS).
Spec comparison
Display
| Spec | LG - C5 OLED 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| Screen sizeⓘ | 77 "lead | 75 " |
| Panel typeⓘ | OLEDlead | Mini-LED |
| Resolutionⓘ | 4K | 4K |
| Refresh rateⓘ | 144 Hz | 144 Hz |
| Peak brightnessⓘ | 1300 nits | 5000 nitslead |
HDR & Smart
| Spec | LG - C5 OLED 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| Dolby Visionⓘ | true | true |
| HDR10+ⓘ | false | truelead |
| Smart OS | webOS | Google TVlead |
| Dolby Atmosⓘ | true | true |
Gaming
| Spec | LG - C5 OLED 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| HDMI 2.1 portsⓘ | 4lead | 2 |
| VRRⓘ | true | true |
| ALLM | true | true |
Frequently asked
Which is brighter, C5 OLED 77 or QM851 Mini LED 75?+
QM851 Mini LED 75 peaks at 5000 nits vs 1300 nits.
Which is better for gaming, C5 OLED 77 or QM851 Mini LED 75?+
C5 OLED 77 offers 144Hz refresh and 4 HDMI 2.1 ports.
Does C5 OLED 77 or QM851 Mini LED 75 support Dolby Vision?+
Both support Dolby Vision.
Spec-level deep dives
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