I have side-by-side iMacs, 21 inch. Early 2009 model and late 2019 model.
Using Xfinity Speed Test, one (the newer) reads 53.7 Mbps download and 20.0Mbps on the older. Same network. Linksys EA 8300 router, Motorola Arris SBG6580 modem. Would the older model have some innate inability for higher speeds perhaps? Thanks for any suggestions.
Yes it's possible that it just doesn't have as much horsepower as the newer one does.
BTW, if you are hanging that Linksys router off of the 6580, do you have the 6580 in bridge mode ?
Hope things hold up for you. Good luck !