Switch-off however is slow as the FET is left to discharge its gate through the 10k resistor. For a switching application (such as PWM) this is inadequate even for moderate loads.
A proper design requires a push-pull driver for the gate - not a 10k resistor.
Good thinking, however, we're trying to solve the OP's problem, not design for Mhz
operation. There is already far too much confusion on this thread [if you read all the
posts]. He's not gonna be switching lights in his automobile at 40Khz.
R * Cin[mosfet] = 10K * 2.8nF = 28 usec.
So, 10K is probably perfectly fine.