You are correct saying that benchmark includes video playback too (irrelevant to you).
I reckon the only benchmark of relevance here is the Math score, and the database.
Hence, my original reply, if you use an external DSD capable DAC, then the processing is done at the DAC, to put things in prespective, I get a Math score of 1900 at work, and I don't have a DSD capable DAC, so JRiver must decode and output in 192KHz to my internal card. It does it with ease, even if I am doing ten other things on the PC at the same time, hence JRiver is not processor hungry! ( and it uses less than 100MB of RAM doing it).
If your DSD iso's are on a NAS, and you are connected to your network through a bad wifi, then there may be glitches.
Don't worry, a lowish core II processor and nominal RAM will play your DSD's.
Just get a used PC with at-least a core II processor 2GB of RAM, get rid of all small fans, get a low speed 100mm (or bigger) fan blowing in, for all your cooling, and you will have a good enough, near silent machine that plays all your music, for little money. If you use it only for your multimedia, then there's no need for antivirus, updates or any other interfering software's either.
Keep your better machines for day-to-day use.