90% Reduction in performance when adding a single character

[ipen]

Hi folks,

Reaching out because I am at a loss. 

In a nutshell, this command has me at 4500mh/s on a 4090:

Code:

hashcat -a 3 -O -m 22500 --hex-charset w.txt -1 61626364656667686A6B6D6E707172737475767778797A41424344454647484A4B4C4D4E 202020?1?1?1?1?1?1?1?1

But adding a single character to this results in a 90% reduction in performance, starts hashing at 450mh/s:

Code:

hashcat -a 3 -O -m 22500 --hex-charset w.txt -1 61626364656667686A6B6D6E707172737475767778797A41424344454647484A4B4C4D4E 20202020?1?1?1?1?1?1?1?1

Util of the GPU is curious in the second instance: idle-busy-idle-busy-idle-busy. Hashcat's util numbers mirror what is illustrated in the attached image.

Something simple I am perhaps missing?