I see the "DSP Limit" is still being reached in the HD500x, albeit at a 'higher' level. Not surprising, really, because of the device design. This argument has been going on for years, and you either like this design or you don't. There ARE Pod HD models that do not have any apparent DSP limit - the Pod HD300/400.
The following snippet is from a post I just made in another thread.
It is not intended to ignite the old debate - it's just intended to clarify (for new readers) two design approaches to the reality that ANY processor has DSP limitations. The options are: hide the limitation and prevent users from using all available DSP in most situations, or expose the limit by putting the user in control of DSP management. Your choice - but there is NO DSP processor that is unlimited. The debate really is whether or not the Pod HD dual-path devices (all models, including the 500x) have 'enough' DSP - but of course there's never enough. The real question is: do you want to be able to use all that is available, or not?
Re: DSP overload - the X3 has its DSP limitations too, as does any processor. Most processor manufacturers guarantee that you will never observe those limits by constraining your selection and placement of FX. In the X3 you can't use both a distortion and overdrive in the same Tone. You are limited to 3 FX blocks from which you can only select one instance from that group of FX. The same constraining design applies to the HD300/400 - you will never encounter the DSP limit because it is engineered away. With this design model, in any preset that uses DSP-light selections for the FX slots, there is a LOT of technically available but actually wasted DSP I prefer the HD500/Pro/Desktop design model. The user is in control of all available DSP, and the selection and placement of all FX is entirely at the user's discretion - up to the point that all available DSP is being utilized; that's when the DSP Nanny steps in and prevents you from doing any more.