Memory problems 'r' us

[cspurgeon1281]

.. Windows 7 64bit /FX8120- 3.1 GA-78lmtUSB3-/
Radeon rx560
CPU-z reads 24gb RAM (24installed) Windows reads 18Gb... only 12Gb usable what is going on

 

[Barty1884]

Which modules are you using, specifically?

I'm assuming these are mis-matched modules? Different brand/speed/timings... ?

 

[cspurgeon1281]

Which modules are you using, specifically?

I'm assuming these are mis-matched modules? Different brand/speed/timings... ?

yes 2 G.Skill @8192 666MHz
2 Crucial Tech @4096 800MHz