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In this sub-session, the Phase 5 Pre-Compiled Constraint Evaluator (PCE) was tested, debugged, and benchmarked. Initial testing revealed a correctness bug where RecordingCS::enforce() used an inconsistent aux column offset during circuit synthesis, causing ~53% constraint mismatches; this was fixed with a tagged encoding scheme (bit 31 flags aux vs input) with deferred remapping. Performance optimization switched the CSR MatVec from sequential to parallel execution via rayon, reducing MatVec time from 34s to 8.8s and achieving a 1.42× overall synthesis speedup (35.5s vs 50.4s baseline). When the user questioned the 375 GB peak memory usage, the assistant traced it to a benchmark artifact (holding old and new results simultaneously) and designed a new pce-pipeline subcommand with inline RSS tracking and malloc_trim. Sequential benchmarks confirmed clean memory drops (155.7 GiB old path → 25.8 GiB PCE static → 181.6 GiB during synthesis → 25.9 GiB after drop), and parallel benchmarks with 2 concurrent pipelines peaked at 310.9 GiB (2× working set + static) then dropped cleanly, validating the memory model for multi-GPU deployments. Documentation was updated in cuzk-project.md with the memory analysis and revised roadmap.