Question GPU memory is a lot less ?

[Lucky dragon]

When I run games in my computer, the GPU memory is very a lot less and my computer's RAM is used a lot, what is the reason for this? Like.
Using in Msi afterburner

GPU =85%
Mem =250mb
Cpu = 81
Ram = 1800
D3d10 = 40 fps

Pc specifications
Cpu= Intel pentium 2180
Ram= 4gb ddr2
Gpu=. Gt730 2gb ddr3
Motherboard= g41 pcie 1.0 x16
OS=. Windows 7 64bit

 

[rgd1101]

It depends on the game.