Hi Sam,
I checked with an engineer that tests performance. There is typically a small hit when forming a team because of the overhead of up to 2-3%, but nothing like what you are reporting. Of course, the configuration and testing method can make a big difference. We are not sure what was meant by "The team is not yet presented to hyper-v." Can you tell us more about your test setup and how the adapter is configured? By the way, what version of Windows or Hyper-V are you using?
When the Hyper-V role is present the adapter's performance profile defaults to the Hyper-V profile. (See FAQs: Performance Profiles for Intel® Ethernet 10 Gigabit Server Adapters for more information.) What profile are you using? Any changes to the configuration that you have made? A good configuration practive is to match the number of RSS queues and CPUs to the number of VMs.
I am looking forward to hearing the details and helping you get the most from your Intel Ethernet adapters.
Mark H