Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | LG - G5 OLED evo 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| Peak brightness | 4000 nits | 5000 nits |
| Refresh rate | 165 Hz | 144 Hz |
| Screen size | 77 " | 75 " |
| HDMI 2.1 ports | 4 | 2 |
| Panel type | OLED | Mini-LED |
| Smart OS | webOS | Google TV |
Between the G5 OLED evo 77 and QM851 Mini LED 75, the G5 OLED evo 77 comes out ahead in refresh rate / screen size, while the QM851 Mini LED 75 wins on peak brightness / smart os. Overall, the G5 OLED evo 77 scores 82.8 and the QM851 Mini LED 75 scores 78.2 on our Mars Score.
Which should you buy?
The G5 OLED evo 77 edges ahead on the Mars Score (82.8 vs 78.2), but the 4.6-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the G5 OLED evo 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 refresh rate, screen size, hdmi 2.1 ports, among others. The single most decisive one: Refresh rate — 14.58% more. 165 Hz vs 144 Hz.
Pick the QM851 Mini LED 75 if you care most about peak brightness / smart os. Its strongest claims are peak brightness, smart os. The single most decisive one: Peak brightness — 25.00% more. 5000 nits vs 4000 nits.
Both ship with comparable dolby vision, 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 - G5 OLED evo 77 or TCL - QM851 Mini LED 75?
LG - G5 OLED evo 77 leads the current Mars Score by 4.6 points.The more useful decision is the trade-off behind that result: compare screen size, panel type, refresh rate, hdmi 2.1 ports against the way you will actually use the product.
Choose LG - G5 OLED evo 77 if…
LG - G5 OLED evo 77 has the measurable edge on refresh rate hz, screen size in, hdmi 2 1 count.
Choose TCL - QM851 Mini LED 75 if…
TCL - QM851 Mini LED 75 has the measurable edge on peak brightness nits, smart os.
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 - G5 OLED evo 77 wins
- ▲Refresh rate — 14.58% more. 165 Hz vs 144 Hz.
- ▲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 — 25.00% more. 5000 nits vs 4000 nits.
- ▲Smart OS: Google TV (vs webOS).
Spec comparison
Display
| Spec | LG - G5 OLED evo 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| Screen size | 77 "lead | 75 " |
| Panel typeⓘ | OLEDlead | Mini-LED |
| Resolutionⓘ | 4K | 4K |
| Refresh rateⓘ | 165 Hzlead | 144 Hz |
| Peak brightnessⓘ | 4000 nits | 5000 nitslead |
HDR & Smart
| Spec | LG - G5 OLED evo 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 - G5 OLED evo 77 | TCL - QM851 Mini LED 75 |
|---|---|---|
| HDMI 2.1 portsⓘ | 4lead | 2 |
| VRRⓘ | true | true |
| ALLM | true | true |
Frequently asked
Which is brighter, G5 OLED evo 77 or QM851 Mini LED 75?+
QM851 Mini LED 75 peaks at 5000 nits vs 4000 nits.
Which is better for gaming, G5 OLED evo 77 or QM851 Mini LED 75?+
G5 OLED evo 77 offers 165Hz refresh and 4 HDMI 2.1 ports.
Does G5 OLED evo 77 or QM851 Mini LED 75 support Dolby Vision?+
Both support Dolby Vision.