nvidia driver shows wrong total memory N580GTX

Opensuse 42.2 leap x86_64 nvidia driver gfxG04 driver 375.39 shows wrong total video memory.
Graphic card MSI N580GTX 3gb.
Only 1536mb instead of 3000mb is shown.

I also have no cuda / gpu support anymore when I want to use my main program blender.
followed this install method:

Open YaST, then click Software Repositories.
Click Add (in the bottom left), then select Community Repositories.
Select NVIDIA Graphics Drivers, then click OK.
Go back to the YaST Control Center and click Online Update.*
Click Extras in the top bar, then click Install All Matching Recommended Packages.*
Click Accept, then wait for installation to complete.*
Restart your computer.