What OS and Version?

Windows 10
PacketSender version 8.3.6
Two computers hooked directly together with 10Gb fiber.

Description of issue

While using the Intense Packet Generator tool, setting the speed to 1250 MB/sec the Stop button does not work. In order to stop sending packets I have to close the application.

I am also only able to send packets at a max rate of about 230,000 packets/sec, how can one send at a higher rate?

Thanks