So, that means no possibility for hardware transcoding on my current setup, even with another CPU if I understand all the above correctly.
(getting a stronger CPU would just bring more 'horsepower' to do the software transcoding)
Coming across @IG-88's efforts to realize nVidia GPU support, it seems wisest for now to see if (when ) that bears fruit, so I could get a suitable nVidia graphics card . The alternative is to get an altogether different hardware setup, which I'd rather not as that would turn out to be significantly more expensive...