Garmin Forerunner 935Garmin Vivoactive 3
Tech specs 
Size47 x 47 x 13.9mm43.4 x 43.4 x 11.7 mm
MaterialLens material: glass
Bezel and case material: fiber-reinforced polymer
Case material: fiber-reinforced polymer and stainless steel
Lens material: Corning® Gorilla® Glass 3
Bezel material: stainless steel
ChargingYesUSB
BatteryLithium-ionRechargeable lithium-ion
Battery lifeUp to 24 hours in GPS mode with optical HR; up to 2 weeks in watch mode including optical HR, activity tracking and smart notifications; up to 60 hours in UltraTrac modeGPS mode: Up to 13 hours
Smartwatch mode: Up to 7 days
Water-resistance5 ATM5 ATM
Weight49 g43 g
SensorGPS/GLONASS, barometric altimeter, compass, accelerometer, gyroscope, thermometer, heart rateGPS, barometric altimeter, compass, accelerometer, thermometer, heart rate
Display240 pixel diameter; sunlight-visible, transflective memory-in-pixel (MIP)sunlight-visible, transflective memory-in-pixel (MIP), 240 x 240 pixels
Screen size30.4mm diameter1.2" (30.4mm) diameter
ColorsSlate Gray, Silver, Champagne - comes with interchangeable bands in various colors.Black, White
OtherPLATFORM: Home Grown OS
PROCESSOR: Unknown
MEMORY: 64 MB
CONNECTIVITY: WiFi, Bluetooth
PLATFORM: Home Grown OS
PROCESSOR: Unknown
MEMORY: 7 timed activities, 14 days of activity tracking data
CONNECTIVITY: WiFi, Bluetooth
Activity tracking 
StepsYesYes
DistanceYesYes
Calories burnedYesYes
ActivityYesYes
FloorsYesYes
SleepYesYes
Heart rate24/7Yes
Stress & recoveryYesYes
Pulse Ox
Respiration rate
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intake
GPSGPS and GLONASS enabledYes
Running featuresVO2 max estimate, recovery advisor, race predictor, running dynamics, calculates distance for indoor workouts, personal records, virtual partner/racerPreloaded running profiles, GPS based distance/time/pace, run workouts, foot pod capable
Swimming featuresLengths, distance, pace, stroke count/rate, calories; stroke type identification; open water swim metrics; swim workoutsPreloaded swim profiles; Pool swim metrics (lengths, distance, pace, stroke count/rate, calories); Stroke type detection (freestyle, backstroke, breaststroke, butterfly); Pool swim workouts
Swim efficiency (SWOLF)
Other - Physiological measurements: Yes (Recovery time, lactate threshold, FTP, HRV Stress Test, V02 Max for running and cycling, Race Predictor, Training Status, Training Load, Anaerobic Training Effect)
- Running Dynamics (with optional accessory)
- Performance condition
- Run/walk feature: Yes
- many other features...
Custom alerts: Yes
Customisable lap screen
Connect IQ™ support: Yes (watch faces, data fields, widgets and apps)
Wireless connectivity: yes
UltraTrac: Yes
- gym workout tracking
- music control, find my phone, etc..
- Built in apps for running, golfing, cycling, swimming, snowboarding/skiing, paddle board, rowing, cardio, walking, strength training, rep counting, yoga, eliptical, stair-stepper and more.
Non-fitness functions 
Smartphone notificationsYesYes
On-board music storage
Connected payYes
LTE
Links 
Affiliate link*Amazon | GarminAmazon | Garmin
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