For a qemu proxmox guest PFSense acts weriedly with the network speed- it gets extremely slow. So her goes the little tweaks that worked for me-
First, I chose Intel E1000 Interfaces instead VirtIO.
Second, in the PFSense webconsole-
In pfSense GUI, System > Advanced > Networking > Tick on-
- Disable hardware checksum offload
- Disable hardware TCP segmentation offload
- Disable hardware large receive offload