Thanks for your awsners.

I testet the following thinks:
I connectet only one Card to the Rack with a PCIE Riser

Asus 1 = 18MHs
Asus 2 = 15MHs
Gainward 1 = 15MHs
Gainward 2 = 12MHs

I can not explain that. The Cards work normal in the single mode but if i connect all carts to the System the MHs is realy bad.

I use the Nvidia 23.21.13.8871 Driver from December 15, 2017.

It is necessary to Change the RAM or Processor?