diable/enable CUDA Sysmem Fallback Policy from command line

a

Build or download https://github.com/Orbmu2k/nvidiaProfileInspector/releases/
run nvidiaProfileInspector.exe -silentImport enable_sysmem_fallback.nip or disable_sysmem_fallback.nip which you will find below.
enjoy. better method coming soon as I iron our some nvapi bs

disable_sysmem_fallback.nip

<?xml version="1.0" encoding="utf-16"?>
<ArrayOfProfile>
  <Profile>
    <ProfileName>Base Profile</ProfileName>
    <Executeables />
    <Settings>
      <ProfileSetting>
        <SettingNameInfo>CUDA Sysmem Fallback Policy</SettingNameInfo>
        <SettingID>283962569</SettingID>
        <SettingValue>1</SettingValue>
        <ValueType>Dword</ValueType>
      </ProfileSetting>
    </Settings>
  </Profile>
</ArrayOfProfile>

enable_sysmem_fallback.nip

<?xml version="1.0" encoding="utf-16"?>
<ArrayOfProfile>
  <Profile>
    <ProfileName>Base Profile</ProfileName>
    <Executeables />
    <Settings>
      <ProfileSetting>
        <SettingNameInfo>CUDA Sysmem Fallback Policy</SettingNameInfo>
        <SettingID>283962569</SettingID>
        <SettingValue>2</SettingValue>
        <ValueType>Dword</ValueType>
      </ProfileSetting>
    </Settings>
  </Profile>
</ArrayOfProfile>