One of the questions people keep on asking on various forums is “I have a Garmin Fenix 6. Should I upgrade to Fenix 7?”. The answer depends very much on your priorities and constraints, but usually the money rationale doesn’t support the upgrade.
One of the differentiators between series 6 and 7 of Fenix (I won’t go into the discussion about Epix 2, that another story with screen preferences and battery life) is the fact that some of the Fenix 7 watches (the more expensive, Sapphire ones) have dual-frequency/multi-band GNSS and claim to have better accuracy (potentially affecting in a positive way the pace/distance and the look of the GNSS track).
I don’t have the Fenix 6X available (anymore) for a comparison, but Fenix 6 series was not well known for its good GPS accuracy, quite the opposite – even though I can’t complain myself – I rely for distance and pace on my Stryd footpod so I didn’t care that much about the GNSS accuracy. In the recent days, I spent some time wearing during running workouts a Polar Vantage V2 and the Fenix 7X and I could easily compare the two in various conditions. When the sky is clear and you’re not running in the forest or between tall buildings, the difference is not dramatic – you could say that this is only a matter of “looks” of the GPS tracks.
When going into the forest, things change a bit .. and the difference is more clear. I mean, besides that time for acquiring the signal – the Fenix 7X is incredibly fast .. Vantage V2 is not bad, but it just can’t compare.
My track has two sides – the left side is more open sky whereas the right side is under the tree cover – that makes a difference when you zoom into those areas – on the left side, the difference is not consistent, it might be interpreted as being the result I worn the watches on different arms; on the right side, the difference is more clear – Fenix 7X with dual-frequency dual band GNSS is able to keep the straight line and Vantage V2 wonders around during both passes through that zone.
So, if you care about the looks of your running GNSS tracks, dual-frequency makes a huge difference if you run in the forest or covered by large buildings. It’s not only that, the pace and distance is impacted in a positive way.
If you’re interested in another comparison, more exciting than mine and covering more devices, take a look at DCRainmaker’s review available here.
In the end, if you use Stryd (like me), the multi-band/dual-frequency GNSS won’t change the game for your running sessions, but it’s clear that this is a good step forward for accuracy.
For reference: Vantage V2 firmware 3.1.1, Fenix 7X SS firmware 8.15beta
Enjoy your running and be well!
Liviu Nastasa 
I have a vertix 2 and the accuracy is crazy good. I don’t know about the Fenix 7 but the new dual frequency generation made my Stryd completely useless. More trouble with Stryd than with my gps now 😳
That’s what I’ve seen as well with Fenix 7X Sapphire Solar, I think they share the same chipset and also I’ve seen comparative tests where Vertix2 and Fenix7 multi band were the leaders by far in accuracy. Maybe I’ll test my Fenix with GNSS and leave the footpod for a while – who knows – depending on the results.
I feel the same way. As you illustrate, the 7x is very good at tracking even under partial cover. But since I run with Stryd and care more about pace, I feel that Vantage V2 is good enough.