NOT USING ALL MY REMAINING MEMORY!!!

[yh1169]

OS: Windows 7 Ultimate SP1
i5 2500k (overclocked 4.5ghz), 1600mhz 8GB ram, 5870 crossfired

I'm running Civilization V and THE MEMORY DEFICIENCY ERROR CONSTANTLY POPS UP WHEN IT REACHES THE 4GB MEMORY USE!!!
the Resource Monitor (ctrl+alt+del --->recourse monitor) shows I have sufficient amount of memory left but this constantly happens..

HELP!

 

[yh1169]

OS: windows 7 ultimate sp1 (64bit) **

 

[Engima]

What motherboard are you using?

 

[yh1169]

p8p67 pro asus