i would try to see if you are already using up all your cores to their full potential.
If not, you may not need to change any hardware.
If so, there is still room for more resources with the same system since you have a K model processor that can be overclocked.
Centucky fried DAW on this forum can you tell all about that option.
A good longterm solution is vienna ensemble pro.http://www.viennaensemblepro.com/
This for two reasons:
- it takes away the asio strain from cubase, and actually it outperformes cubase on the multicore front in terms of efficiency even when used on a single system.
- it opens the ability to have multiple computers in one DAW setup over LAN
This way you are only limited in terms of processing power depending on the budget you have.
If you look around on the forum, you will note that a lot of the guys with larger setups use that program.
This is as such not a reference, but it can count as an indication.
For live usage there is also another benefit using VEP.
Since it is server based and the fact that you can preserve instances, you reduce loading times significantly. Your sounds remain loaded even when changing cubase's cpr's.
hope this is somewhat of an answer you were looking for.