Most used PCs for sale started off as business machines. They usually buy from the big brands that can provide enterprise warranty support and volume discounts. AMD released Ryzen in 2017. Add up the time for AMD to convince Dell/HP/Lenovo to design, qualify, and release an AMD model. Add the time for significant uptake into the market. Finally add three years for the AMD PCs to get retired from office use.
Yet the website here seems to only show less than 100. I’m saying its method of organizing the data is not accounting for the fact that there are thousands of AMD mini PCs for sale on eBay.
