The only issue I see is at about 3000 meters the near coastlines appear squared off and serrated.However, to what extent this is to my old-ass computer I am not sure.
Yes, about that you are right ... we downloaded the satellite data to make the map, not from the usual MicroDem site, but from another site that specializes in high latitude map data. If you need anything from the arctic regions, Microdem just doesn't have it available.
However, there is an issue with the other site's mapdata showing very geometric shaped, block shaped coastlines. Most of the coastlines were like a succession of square/rectangular building blocks of various sizes, neatly piled up to one another. We had to adjust the coastline data by hand, coloring in by hand an approximation of irregularity. It worked fairly well, at least when flying at lower altitudes. But with all the coastline there is ... well, it was quite a length all in all. I hardly ever fly above 1500m and suppose i just didn't really notice the blockiness at that altitude.
We did the same serious kind of manual altering for the winter map_C, to create an impression of having ice around the coasts and ice floes here and there ... the winter map also has the ice pack way up north ... but it's not marked on the map. The only little blemish is that pop-up trees will appear here and there on ice ...
So it's not your computer, but an inherent flaw in the map data ...