32 bit Operating systems such as OS/2 can only address 4GB of ram. The top of the ram is used by PCI devices, video driver etc so generally about 3.5GB give or take. If you are using builtin graphics, you might be able to reduce how much it uses in the BIOS and claim a bit more but 3.2 MB is not unusual, here,
D:\>mem -v
Total physical memory: 12,169 MB
Accessible to system: 3,241 MB
Additional (PAE) memory: 8,928 MB
Resident memory: 179 MB
Available virtual memory: 1,896 MB
Available process memory:
Private low memory: 318 MB
Private high memory: 2,240 MB
Shared low memory: 216 MB
Shared high memory: 1,242 MB
So much the same as you. With ArcaOS, the inaccessible memory can be used for a ram disk, 8GB's here.