It's probably fairly safe to assume that the Yamaha lead isn't where the fault lies.
After all, Yamaha has been involved at the leading edge of MIDI for more than thirty years. Their equipment is known for its reliability.
A MIDI note on message is just 3 bytes of data. Okay, encapsulated in a USB packet it's a bit bigger. But it should take around a millisecond to transmit.
Digital audio, however, consists of 44100 samples each of two bytes (16 bits) x 2 for stereo, per second. (Assuming CD quality.)
When the note on message is received it has to be passed through Cubase to the Drummer then the Audio generated and sent to the mixer via USB.
Getting that created and out through the USB port takes time. This is 99% of the time where the latency is introduced.
I have a battered old laptop, still running XP, with a Centrino Dual core and 4GB of RAM, and I can get the latency down to about 6 ms using ASIO drivers.
So it's not processing power or RAM, I'd suggest.
Try cancelling the resampling, that might shave some time off.