Is ACS override on a B460 safe for HBA and RTX 3060 Ti passthrough?

Using ACS override on a B460 board to pass through an HBA and an RTX 3060 Ti will usually work for a single-user homelab, although it is a compromise. The override forces artificial IOMMU separation where the chipset does not provide proper ACS isolation. That weakens DMA isolation, which matters in multi-tenant or hostile environments, but in a home lab the risk is typically acceptable.

Most of the discussion was less about whether passthrough will function and more about whether running TrueNAS in a VM makes the architecture too complex. Multiple experienced users pointed out that a TrueNAS VM with HBA passthrough adds layers without clear benefit if you are not using advanced TrueNAS-specific features. Proxmox can manage ZFS natively. You can mount the ZFS dataset directly on the host and share it via a lightweight LXC, such as a simple fileshare container. That uses less memory, avoids double virtualization, and makes backups through Proxmox Backup Server simpler.

On performance, one clarification came up: L2ARC does not speed up writes. It is a read cache only, and it mainly helps small random reads when RAM ARC is insufficient, so for large sequential media writes it provides little or no benefit. If you want faster writes, a proper SSD pool or mirrored NVMe ZFS pool for active workloads is far more effective.

Nobody raised major red flags about running GPU and HBA passthrough at the same time, beyond the usual BIOS setup such as enabling VT-d and Above 4G decoding.

The general advice was to keep the design minimal: if Proxmox can handle storage directly, a full NAS VM may add more moving parts than value.