An open-access longitudinal network engineering research dataset evaluating single-thread vs. multi-threaded (2 to 32 parallel TCP connections) throughput across high-latency round-trip times (15ms to 280ms RTT) and packet loss environments using RFC 9110 HTTP Range byte slicing. Telemetry captured and empirically benchmarked using the Vortex Downloader acceleration engine (https://vortexdownloader.org). Detailed technical architecture and benchmark analysis: https://vortexdownloader.org/multi-threaded-download-acceleration-explained/. Cross-Repository Citations & Persistent Identifiers: Harvard Dataverse Repository: doi:10.7910/DVN/EZ1KXS Wikidata Semantic Entity: Q141496440 (Vortex Downloader) Software Heritage Universal Archive: GitHub Origin Snapshot Lead Investigator ORCID: 0009-0007-4383-9913 (Hammad Shaikh)