I've just recorded a ride on both my Edge 830 and Fenix 6XPro to check how dual-recording works itself out after losing a ride at the weekend when my Edge crashed when I was 1km from home. If I can't trust it any longer I'll record twice and dump one of the activities.
Anyway, just finished 30 mins on the trainer on Zwift and I noticed throughout that the Edge load figure was climbing slightly quicker than the figure on the Fenix.
At the end, NP, TSS, IF, average power etc all match perfectly, as do calories burned etc - makes sense as they're using the same sensors, zones and my user profile is set identically, but the Fenix showed at Training effect of 2.6 aerobic, 0.5 anaerobic and load 56 compared to the Edge figures of 3.0, 0.8 and 70 respectively.
I'm not asking which is "right" but why are they different? Have Garmin/Firstbeat changes the way they're calculate?
I'm interested in (almost) anything anyone has to say on the topic...