Do you have the Epix 2 AND Instinct 2X? Accuracy issues.

net1994 over 2 years ago

Hi All. I just got the Instinct 2X. I also have the Epix 2 non-pro. I love the look of the Instinct and got it because it was on sale and has the multi-band GPS. However the I2X seems less accurate than Epix, even though they have the same GPS chipset as well as heart rate monitor. On a recent run, I had the Epix 2 on my left arm and the I2X on the right. The heart rate average for the run was 25 bpm higher on the I2X than the Epix.. Both watches were snug on the wrist and not moving around. Also, the distance recorded on the I2X was noticeably shorter and the GPS track was noticeably worse than the Epix. And all the GPS settings are set to the same on both watches. Also, the sleep tracking isn't as accurate as the Epix. To me, these differences aren't minor and would lead to me probably returning the watch. I called Garmin support and they couldn't see any setting issue that would cause any of these issues.

Anyone else here notice the I2X is a bit off compared to an Epix 2 (non-pro) or even Fenix 7 (non-pro)?

0 trux over 2 years ago

net1994 said:
On a recent run, I had the Epix 2 on my left arm and the I2X on the right. The heart rate average for the run was 25 bpm higher on the I2X than the Epix..

And why do you think Epix was correct? Maybe you could compare it with data from a chest strap, to find out which of them is right.

net1994 said:
Also, the distance recorded on the I2X was noticeably shorter and the GPS track was noticeably worse than the Epix.

That's possibly not due to the worse GPS accuracy, but rather because of different calibration of both watches. Unfortunately Garmin does not use pure GPS distance, but rather a combination of GPS distance and accelerometer based data for calculating the distance (and pace). And when the watch is not calibrated accurately (or not used long enough yet), it very often leads to underreporting of the distance, or overreporting it.

You can verify it by simply saving both activities as Courses in Garmin Connect Web, and comparing the distances there. The course distance is then recalculated, using the GPS trackpoint coordinates, ignoring so the accelerometer data. I bet, the distance saved into the course by Instinct will increase significantly.

As for the sleep - I have no other watch to compare to, and without a polysomnography it is hard to guess whether the sleep stages correspond to the reality or not, but minimally as for the bed and wake-up times, and as for the woke stages in the sleep, my Instinct is pretty accurate, and never failed on me.