I think if you were to upgrade then you’d be wanting a new CPU and motherboard, which is pretty much a new box.
ROCK doesn’t enable you to run HQP on the same machine. ROCK takes over the machine and runs RoonServer exclusively. You can run HQP on another machine, but you wouldn’t buy two computers in order to do that, better to get one that can run both.
If you’re not wedded to HQP then you may not need to upgrade immediately. I think your current machine could upsample to 192 kHz in the Roon DSP Engine. Worth trying.
Having said that, any of the ROCK capable i5 NUCs will upsample to 192 kHz in Roon all day long without breaking a sweat.
If you were to consider a ROCK NUC as Core, then I’d encourage you to look at a network endpoint as well, instead of a direct USB connection between the Core and the Lampi DAC. A network endpoint enables some isolation from the inherently noisy computer environment.
If you wanted to retain HQP capability, then any upgrade should take into account your intended use. Upsampling to 192 kHz PCM or greater with HQP using the xtr filters will be fine with an i5. Once you start looking at upsampling to DSD 256 or DSD 512 using xtr filters then you will want a current i7 and a good nVidia graphics card for CUDA offload.
By way of example, you can see the parts list for my current server for Roon and HQP here. If you were interested in that sort of build then you would probably find a computer shop able to assemble and install everything for you if you bought through them. I enjoy
assembling them myself, but not everyone does. Even with this fire breather I have to use the xtr-2s version when upsampling to DSD 512.
But if you weren’t ever interested in upsampling to high DSD rates in HQP then an i5 running Windows 10, RoonServer and HQP is what I’d suggest. I also like the microRendu as a network endpoint.