How do I get 64-bit?

Nero would be showing 70% of about 4 GB.

 

What brings you to that conclusion?

 

32 bit can address 4 GB of RAM total, but in function a 32 bit application addresses only about half of that (divided in two). Now consider that 70% of 64 GB would be 44.8 GB of used RAM which Nero is incapable of addressing. In reality your 70% of used RAM is closer to 1.4 GB t0 2.1 GB. No application can use a system's maximum whether 64 bit or 32 bit since the operating system reserves some for its own use and that of anything else running in the background.

 

Thanks for the reply !