PCIE passthrough NIC (SFP+ card) - very slow performance


Jul 13, 2021
Here's what I have:

Proxmox installed on a very powerful machine (RAM/CPU-wise). I have granted generous amount of CPU + RAM to pfSense guest.

Now I have a 10gb uplink 9000 MTU connection for WAN. It's fiber / SFP+. I am doing full PCIe passthrough. (all functions of card selected, PCIe selected)

Everything seems to be choppy. Download speed is almost capped at 600Mbps-ish, upload is capped almost at 200Mbps-ish. It should be at least 940/940 (have done the test with a laptop, bypassing Proxmox+pfSense)

I have TSO, LRO boxes checked in pfSense, they are disabled. I have set MTU to 9000, I do pciconf -lv in pfSense and can clearly see PCIE devices.

I have been trying many many things, nothing works. Virtualization shouldn't really have this much effect especially since I'm doing PCIe passthrough, but it does. Something is off. What am I missing? My machine type is q35 and I defined the CPU type manually (AMD Rome) and my pfSense shows hardware crypto is enabled as well.

Still everything is slow. Any suggestions for me?


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