Read in or write out large Number of Stepper Motor Delays

Hi, I am seeking advice on a project. I have been working with an arduino for all of 3 days, so please bear with me.

I am using an Arduino Uno to control a stepper motor, and I wish to send random delay values to the motor, so it runs at a random, but continuous speed. The trick is, I want to have a record of what these random inputs are, for future reference or study. Printing the inputs to the serial doesn't seem like an option, because with the low power processor, this dramatically slows down the running of the motor. So, basically I am wondering:

Can I write randomly generated values to a text/csv file on my computer without using the serial?
A second option, can I read in randomly generated values from a file, into arduino, without having the serial slow down the motor?

From my reading on the issue so far, it seems like an SD card might be my best option, but I just wanted to check if anyone has ideas of how to do it without an external storage device first. Thanks!

Can I write randomly generated values to a text/csv file on my computer without using the serial?
A second option, can I read in randomly generated values from a file, into arduino, without having the serial slow down the motor?

From my reading on the issue so far, it seems like an SD card might be my best option

No
Yes
Yes.

Something to try first would be to increase the baud rate on the serial port if you haven't already - 9600 is typical in examples, but it's sloooooooow.

I was able to make it work by raising the baud rate, in addition to randomizing the motor delay every 10 iterations, instead of every iterations. These changes seem to work, and I think I will just copy/paste the random outputs from the serial monitor, although I'm sure there is a better way to do it. Thanks for the tip about adjusting baud rate!