Can that miner use more than 1 thread/core?
Edit your config.txt:
2 cores
"cpu_threads_conf" :
[
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 0 },
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 2 },
],
4 cores
"cpu_threads_conf" :
[
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 0 },
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 2 },
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 4 },
{ "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 6 },
],
etc...