So you want to run the Roon ‘Core’ on the Qnap? If so then there are minimum requirements as well as other recommendations. It has to be an x86 CPU I believe. @crieke is the man who may be able to tell you more Qnap specifics.
Yes, if the core should be running on the QNAP a 64-bit x86 cpu is required. I have no experience with AMD CPUs which are used by some QNAP models. Roonlabs recommends an i3 or higher. On option for i3 processors (or higher) can be found for example in the TVS-x71 series.