unfortunate the rpi-3 only has usb 2 ports which limits what i am about to post about this taken in mind you could use a “zram-config” or similar to utilize a high speed usb stick …it would need to most likely need to modify the structure of the program or utilize a created swap file on a usb stick…it would need to be as high speed as the usb 2 bus can manage here is a link for you to have a look at with some modding of its code it may be an alternative…
