...when the map would only download at a peak of just over 2MB/s. I use a Kingston DataTraveler microDuo 3.0, which has a claimed write speed of 15 MB/s on USB 3.0. The estimated time left kept going up. Last time it was nearly 4 hours.
What I realised was that the limitation was actually my USB stick, maxing out at 100% transfer. I cancelled the download, and restarted it using my main SSD as the target, and it downloaded at close to the 79Mbps of my fibre broadband. That is around 9MB/s, 4 1/2 times faster; it only took around 45 minutes. Then copying to the USB stick took another 40 minutes, which it did at up to 11MB/s, so overall a big saving of time.
Looking at Windows Resource Manager during the two different downloads, the clear issue was all of the little files in the update, so that each one would start and stop downloading, and because it is using a download manager, parts of files are coming from various sources. That isn't what even a fast USB stick is good for.
I would suggest that the recommendation to directly create the update on the USB stick is not the quickest.
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Why do we need the full Europe? Surely it would be better if we could choose to just update UK only, then if we were to take the car abroad we could at that point download the relevant parts of Europe. I get sick of selecting to navigate to a location or a POI for it to show me choices all across Europe.
Just imagine the cost of 18.20 GB download for the thousands of Volvo car drivers. If not a sterling cost, then time taken and bandwidth wasted. And we've all had to buy 32GB or more USB sticks that we can't use for anything else.