Windows 7 x86 (installed on Dell 5820 Tower with 32GB RAM) has only 1.18GB usable RAM

Here are 2 pictures for the previous post.

32 bit Windows versions are limited to 4GB of RAM.  Its a limitation of Windows, not a hardware limitation.

64 bit versions do not have the limitation.

A typical 32bit Windows install will have 3.45GB physical RAM available, as is the case for all my previous install of 32bit Windows on other PCs. But this install of "Windows 7 Home Premium x86"on Dell 5820 only has 1.18GB RAM. The question is why there is such a big difference between 3.45GB RAM and 1.18GB RAM. An install with 3.45GB Physical RAM is viable because legacy software will run very well there, while an install with 1.18GB physical RAM is not viable.

Here are 2 pictures showing 3.45GB RAM with "Windows 7 Home Premium x86" installed on another PC.

Here are 2 pictures showing 3.45GB RAM with "Windows 10 Pro x86" installed on another PC.

Maybe because 32-bit OS does not support quad channel memory and your Windows 7 32-bit can not access to all four channel memory in the 5820, just partially.

@Chino de Oro​ 

A very thoughtful reply, but I have 2 x 16GB memory in Dell 5820, so only two channel memory is active. I have a Lenovo Think Server TS140, with 4 DIMM slots, filled with 4x4GB RAM. "Windows 10 Pro x86" and "Windows 7 Home Premium x86" installed on TS140 still have 3.45GB physical RAM available.

Still, 1.18GB is a very odd number.

@daniel2024​ 

A typical 32bit Windows install will have 3.45GB physical RAM available, as is the case for all my previous install of 32bit Windows on other PCs. But this install of "Windows 7 Home Premium x86" on Dell 5820 only has 1.18GB RAM. The question is why there is such a big difference between 3.45GB RAM and 1.18GB RAM. An install with 3.45GB Physical RAM is viable because legacy software will run very well there, while an install with 1.18GB physical RAM is not viable.

Here are 2 pictures showing 3.45GB RAM with "Windows 7 Home Premium x86" installed on another Think Server TS140.

Here are 2 pictures showing 3.45GB RAM with "Windows 10 Pro x86" installed on Think Server TS140.

@daniel2024​

A typical 32bit Windows install will have 3.45GB physical RAM available, as is the case for all my previous install of 32bit Windows on other PCs. But this install of "Windows 7 Home Premium x86" on Dell 5820 only has 1.18GB RAM. The question is why there is such a big difference between 3.45GB RAM and 1.18GB RAM.

An install with 3.45GB Physical RAM is viable because legacy software will run very well there, while an install with 1.18GB physical RAM is not viable.

@Chino de Oro​ 

So there is a possibility that if I populate all 8 memory slots, i.e., 8x4GB instead of 2x 16GB, the installed 32bit Windows may actually see 3.45GB?

Re:   The question is why there is such a big difference between 3.45GB RAM and 1.18GB RAM.

Maybe because you are installing unsupported OS on your 5820.

Your Precision 5820 support these operating systems:

BIOS
Red Hat® Linux 7.3
Red Hat® Linux 7.5
Red Hat® Linux 8.0
Red Hat® Workstation 7.3
Ubuntu 20.04 LTS
Ubuntu® 16.04
Ubuntu® 18.04 LTS
Windows 10 IoT Enterprise LTSC 2019
Windows 10, 64-bit
Windows 11
Windows 7, 64-bit

@Chino de Oro​ 

You are right. 32bit Windows is not supported. But my question is: Are there any settings or hardware choice on Dell 5820 that makes running 32bit Windows impossible?

When the hardware does not support the 32-bit OS, obviously there is no setting options to make it become compatible.  Not support does not mean it does not work.  When working, it may not fully compatible, like in your case. 

Solution, when the 5820 hardware does not support 32-bit instructions OS, installing it on older hardware should meet your needs and resolved all your issue. 

Why not simply using a virtual machine to install and run those os on the 5820 ? You've the added benefit of running the host and guest os concurrently, too.

You can use virtualbox or even vmware workstation ( that now is free )

Edit,

as for why the 1.18GB of free ram .. is due to your GPU Vram. Gpu ram is counted in the 4GB limit

Moreover, you could just try enabling / forcing PAE

Physical Address Extension - Win32 apps | Microsoft Learn

@mazzinia_​ 

My video card comes with 8GB GDDR5 RAM, and doesn't use system RAM, unlike some of the old video cards that need System RAM to supplement.

@mazzinia_​ 

PAE doesn't help. For some reason, this install doesn't see enough RAM in the system to secure 3.45GB for its use.