Processors Reference
The Processors panel controls the number of vCPUs and the emulated CPU model. Which CPU options are usable depends on the architecture selected for the guest (see the Architecture reference).
CPU model by architecture
Section titled “CPU model by architecture”| Architecture | Default machine | CPU model |
|---|---|---|
| x86_64 | i440fx / q35 | Full PVE CPU model list (host, kvm64, named Intel/AMD models, custom) |
| aarch64 | virt | A CPU model is applied; defaults are provided by the virt machine |
| sparc | SS-5 | Not configurable — the machine provides a fixed CPU |
| sparc64 | sun4u | Not configurable — the machine provides a fixed CPU |
For the SPARC architectures the WSH patches intentionally do not emit a -cpu argument; the selected machine (SS-5 / sun4u) provides its own processor, so the CPU type field is ignored.
SPARC limitations
Section titled “SPARC limitations”SPARC emulation is sensitive to the guest operating system:
- sparc32 (SS-5) is usually limited to a single CPU and around 512 MB of RAM, depending on the OS.
- Installation can be slow and host CPU usage may sit near 100% for the emulated core — this is expected. Pinning the VM to a low-frequency core, or keeping these guests on a test host, avoids reducing performance for other guests.
Further reading
Section titled “Further reading”- Read about CPU types in the Proxmox VE documentation
- Read about CPU emulation in the QEMU documentation