Rate Limit of Injection Frame

[MoChKa]

Does anyone knows the highest VHT rate in real scenario according to the setting: "to inject frames with ac rates use the VHT field in the radiotap header" ?

I just want to know whether the injection frame can be compared to the normal TCP in case of rate comparsion. Because in my test, TCP can achieve at least 70Mbps between two devices. But when I using injection frame to communicate beteween two endpoints, I only get 40Mbps. (Both of them start the monitor mode)

Thanks !