Physical Memory?

[Zyrandiel]

I have a laptop that says It has a 4GB RAM. But when I check the specs out it says 3GB Physical memory only. What does it mean? I'm concerned about this because I'm trying to use Autocad Civil 3D which requires 4GB RAM. But it keeps hanging up, so I'm guessing this is due to that "3GB Physical memory" note. So I'm planning to use Civil 3d 2009 which requires 3GB RAM. But in the system requirements provided by Autodesk for Civil 3D 2009, it says to use the 3GB switch for 32-bit OS's. What does that mean? By the way I'm using windows 7 Home Premium 32-bit.

 

[Dwarf]

A 32-bit operating system can only access 4GB worth of address space. Into that, we need to factor in I/O devices and any other hardware. The result is that actual physical memory that can be used will range from 2.75GB to 3.25GB, dependant on the hardware.

 

[bobkn]

I have a laptop that says It has a 4GB RAM. But when I check the specs out it says 3GB Physical memory only. What does it mean? I'm concerned about this because I'm trying to use Autocad Civil 3D which requires 4GB RAM. But it keeps hanging up, so I'm guessing this is due to that "3GB Physical memory" note. So I'm planning to use Civil 3d 2009 which requires 3GB RAM. But in the system requirements provided by Autodesk for Civil 3D 2009, it says to use the 3GB switch for 32-bit OS's. What does that mean? By the way I'm using windows 7 Home Premium 32-bit.

AutoCAD Civil3D requires 4GB of RAM? Not according to Autodesk:

Autodesk - AutoCAD Civil 3D - System Requirements

(1GB required, 4GB recommended).

A PC running a 32 bit desktop version of Windows won't have 4GB of RAM addressable in Windows:

Memory Limits for Windows Releases (Windows)

That may not explain what you're seeing, though.

32 bit applications are normally limited to use 2GB of RAM, but there's a switch that allows that to increase to 3 GB. Autodesk decribes it:

Autodesk - AutoCAD Civil 3D Services & Support - Enabling 3GB switch on Windows Vista

 

[Zyrandiel]

Okay, I stand corrected, and thanks. but why does it keep hanging up? when other users don't seem to have a problem with it. by the way, it's Autocad civil 3d 2011.