Yes, testing iperf from those VMs to another LAN machine machine unsurprisingly never exceeds 1Gbps (my other LAN machine doesn’t support 2.5), but VMWare is still slower. Maybe it’s due to Workstation using the 13700k e-cores, as someone else commented.

The thing is since my Win11 PC is hosting those 2 VMs I’d expect VM-HOST/HOST-VM network transfers to be faster, even using NAT instead of bridged, yes, it does improve the transfer speeds. but VMWare is still behind Vbox, even with vmxnet3 instead of e1000.

Anyway, thanks for the reply, it might as well come down to being a “Windows thing”, I never had these inconsistencies on a proxmox host, for example.

Win11, Z690, 13700k, 32GB DDR4, 2.5Gbit Realtek Ethernet NIC, Samsung 980 PRO NVMe.

I just installed Debian 12 on both VMWare Workstation (10.1.2.60) and VirtualBox (10.1.2.108), both using 4 “CPUs”, 4GB RAM, both using a bridged network to my one and only Realtek NIC. Everything else is default (even though I also tried with “vmxnet3” on VMWare, no difference). Running iperf3 on my Windows Host (10.1.2.15) and testing from both VMs produces these results.

I host my media server as a VM on VMWare and I don’t understand why Virtualbox is this much faster.

Hyper-V is disabled, Open-VM-Tools installed on Workstation VM.

If you could help me trying to figure out what’s appening or pointing me in the right direction to debug this I’d be grateful.