How many cores do you have and what are you setting the affinity to? What you must understand is the enabled cores are based on the binary representation of the hex number you put in the command lime, the cores are from right to left, lowest to highest.
For example, for an 8 core machine the cores would be numbered 7,6,5,4,3,2,1,0 and turning the bit on enables each core, so to use cores 0 to 6 you’d need to flip bits 1-7 on, 01111111 in binary = decimal 127 = hex 7F - “7F” is the affinity you pass.
for a six core machine to use cores 0-5 you’d need to flip bits 1-5 on, 011111 = decimal 31 = hex “1F” and so on.
Cubase will crash if core 0 (bit 1) is disabled and it seems to prefer contiguous unbroken strings of enabled cores.