Is it possible to differentiate between CPU and GPU projects?
Unfortunately they chose to call both period_search but the plan_class is different.

Well, they don't just call it the same name, it is the same application doing same work and generating same results, just running on different type of processor. That's same for all projects, not just Asteroids. plan_class is different for every application version, even two different CPU versions have different plan_class, for example SSE2 and AVX or whatever (or different platform). Same for different GPU versions. But all those app versions are the same application from BOINC's point of view, you can see that in your client_state.xml, you have one <app> and one or more <app_version> tags, all of them with same <app_name> in them, just different <platform> and/or <plan_class>, which is optional btw., my Milkyway CPU app does not have any <plan_class> since it's the only CPU app version.

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