i7 3960x with 4gb ram but only 3.15gb usable

[VikoMKD]

hello my friend has i7 3960x with 4gb ram and gt 710 and a 64bit windows why only 3.15gb is usable?

 

[Pinhedd]

What motherboard does he have?

 

[ss202sl]

There's always some ram reserved for hardware.

 

[Pinhedd]

There's always some ram reserved for hardware.

Absent an IGP the hardware reserve is typically around 20MiB.

I'd be willing to put money on the motherboard having a legacy PCI slot