ethminer --help-ext cu

ethminer 0.19.0-17+commit.23d537a0
Build: windows/release/msvc

CUDA Extended Options :

Use this extended CUDA arguments to fine tune the performance.
Be advised default values are best generic findings by developers

--cu-grid-size INT [1 .. 131072] Default = 8192
Set the grid size
--cu-block-size UINT {32,64,128,256} Default = 128
Set the block size
--cu-devices UINT {} Default not set
Space separated list of device indexes to use
eg --cu-devices 0 2 3
If not set all available CUDA devices will be used
--cu-parallel-hash UINT {1,2,4,8} Default = 4
Set the number of hashes per kernel
--cu-streams INT [1 .. 99] Default = 2
Set the number of streams per GPU
--cu-schedule TEXT Default = 'sync'
Set the CUDA scheduler mode. Can be one of
'auto' Uses a heuristic based on the number of active
CUDA contexts in the process (C) and the number
of logical processors in the system (P)
If C > P then 'yield' else 'spin'
'spin' Instructs CUDA to actively spin when waiting
for results from the device
'yield' Instructs CUDA to yield its thread when waiting for
for results from the device
'sync' Instructs CUDA to block the CPU thread on a
synchronize primitive when waiting for results
from the device

ethminer --cu-parallel-hash=8


ethminer 0.19.0-17+commit.23d537a0
Build: windows/release/msvc

Error: The following argument was not expected: --cu-parallel-hash=8