Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch 7 (44mm) |
|---|---|---|
| Battery life | 672 h | 40 h |
| Peak brightness | 2000 nits | 3000 nits |
| Weight | 68 g | 34 g |
| Water resistance | 10 ATM | 5 ATM |
| Display size | 1.5 " | 1.47 " |
| ECG | false | true |
Between the T-Rex 3 and Galaxy Watch 7 (44mm), the T-Rex 3 comes out ahead in battery life / water resistance, while the Galaxy Watch 7 (44mm) wins on peak brightness / weight. Overall, the T-Rex 3 scores 62.7 and the Galaxy Watch 7 (44mm) scores 70.9 on our Mars Score.
Which should you buy?
The Galaxy Watch 7 (44mm) is the clear pick on raw spec strength, leading by 8.2 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 T-Rex 3 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are battery life, water resistance, display size. The single most decisive one: Battery life — 1580.00% more. 672 h vs 40 h.
Pick the Galaxy Watch 7 (44mm) 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, weight, ecg, among others. The single most decisive one: Peak brightness — 50.00% more. 3000 nits vs 2000 nits.
Both ship with comparable spo2, so those specs do not separate the two — focus on the differences below.
Bottom line: the Galaxy Watch 7 (44mm) is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Amazfit - T-Rex 3 or Samsung - Galaxy Watch 7 (44mm)?
Samsung - Galaxy Watch 7 (44mm) leads the current Mars Score by 8.2 points.The more useful decision is the trade-off behind that result: compare display size, battery life against the way you will actually use the product.
Choose Amazfit - T-Rex 3 if…
Amazfit - T-Rex 3 has the measurable edge on battery life h, water resistance atm, display size in.
Choose Samsung - Galaxy Watch 7 (44mm) if…
Samsung - Galaxy Watch 7 (44mm) has the measurable edge on peak brightness nits, weight g, has ecg.
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 Amazfit - T-Rex 3 wins
- ▲Battery life — 1580.00% more. 672 h vs 40 h.
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Display size — 2.04% more. 1.5 " vs 1.47 ".
Why Samsung - Galaxy Watch 7 (44mm) wins
- ▲Peak brightness — 50.00% more. 3000 nits vs 2000 nits.
- ▲Weight — 34.00 g less. 34 vs 68.
- ▲Has ECG.
- ▲Has Cellular.
Spec comparison
Design
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch 7 (44mm) |
|---|---|---|
| Case size | 48.5 mmlead | 44 mm |
| Weight | 68 g | 34 glead |
| Case material | polymer | aluminum |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch 7 (44mm) |
|---|---|---|
| Display size | 1.5 "lead | 1.47 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nits | 3000 nitslead |
Health & Fitness
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch 7 (44mm) |
|---|---|---|
| ECG | false | truelead |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | truelead |
Battery & Connectivity
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch 7 (44mm) |
|---|---|---|
| Battery lifeⓘ | 672 hlead | 40 h |
| GPS | true | true |
| Cellular | false | truelead |
| NFC | false | truelead |
| OS | Zepp OSlead | WearOS |
Frequently asked
Which has longer battery life, T-Rex 3 or Galaxy Watch 7 (44mm)?+
T-Rex 3 lasts 672 hours vs 40 hours.
Do T-Rex 3 or Galaxy Watch 7 (44mm) support ECG?+
Galaxy Watch 7 (44mm) supports ECG; T-Rex 3 does not.
Which has cellular, T-Rex 3 or Galaxy Watch 7 (44mm)?+
Galaxy Watch 7 (44mm) offers a cellular variant; T-Rex 3 is Wi-Fi only.