What is wrong with my RAM?

Whatever I do my PC never seems to use much of is vast store of RAM.

This is true for all three of our solidworks PCs.

This is typical of mine

This is actually the better of the three, the other two seldom (perhaps never) use more than 4 Gb.

So how do I get it to use more ram and get the value out of all the ram we have? which we are advised to have fitted, but seems to do nothing?

Is anyone succeeding in getting value for money out of their RAM?

System spec

DELL Precision Tower 3620

Operating System

Windows 10 Enterprise 64-bit

CPU

Intel Xeon E3 1240 @ 3.50GHz 23 °C

Skylake 14nm Technology

RAM

24.0GB Dual-Channel Unknown @ 1063MHz (15-15-15-36)

Motherboard

Dell Inc. 09WH54 (U3E1) 28 °C

Graphics

K242HL (1920x1080@60Hz)

K242HL (1920x1080@60Hz)

4095MB NVIDIA Quadro K2200 (NVIDIA) 38 °C

Storage

238GB LITEON LCH-256V2S-11 2.5 7mm 256GB (SSD)

931GB Seagate ST1000LM044 HN-M101SAD (SATA)

Solidworks professional 2016 SP5.0

My attempts to understand this via google fail and there is a lot of half knowledge out there...

SolidworksGeneral