Both Azul Zulu Builds of OpenJDK and Azul Zulu Prime Builds of OpenJDK are JVMs and are available not only for the latest stable JDK major version but also for earlier major versions like JDK 8 and others as supported products.
Azul Zulu Prime's typical use cases are applications with requirements regarding low latency response time or huge heap sizes in the range of hundreds of GBytes up to a maximum of 20 TBytes or both combined. Azul Zulu Prime is limited to Linux x86 64 bit. Azul Zulu Prime includes its own pauseless Garbage Collection implementation (C4) and its own JIT compiler implementation (Falcon).
Azul Zulu Builds of OpenJDK covers more general use cases as it is mainly OpenJDK with its Garbage Collectors like CMS GC, G1 GC, Parallel GC and the Hotspot JIT. It is available for a large variety of CPU architectures and Operating Systems from servers over desktops to embedded systems.