Using an ESXi with vcenter 6.5 installed. I have a 10G lan connected to a 10G test source. I verified the output of the test tool is an actual 10G using a physical machine. When connected to the ESXi we only see 3.5GB on a virtual machine, also there are no other Vm connected to that port and vswitch and we are using a 10G VMXNET3 vlan. There are no CPU or RAM maxing out, so I guess that isn't the problem.
We also connected the LAN to the VM with direct connection (allocation the lan card on the pci level to the machine) and got 10G.
Is hypervisor is limiting the possible connection speed? Is there a workaround?