Problems mixing memory

[Wadewilson123]

Ok had 8 gig mem for a while went to get another to set it to 16 gb it shows up as 16 but only 7.79 available ?? The memory I had originally with no probs was a 4gb micron tec pc3 12800 and a Kingston of the same now I got 2x corsair of the same speed and this problem has occurred

 

[Tradesman1]

What version of Win? If 7 Home basic it can only use 8GB, If premium or higher should use all 16GB. Let us know, if it is Home premium or better we can try a couple of things, no guarantees since there is never a guarantee when mixing DRAM

 

[Wadewilson123]

It's windows 8.1 64 acer v3 772g its got 4 memory slots also capable of 32gig as far as I know

 

[Tradesman1]

All right, let's try the new sticks in slots 1-3 from CPU and the old in 2-4, and try raising the DRAM voltage + 0.06, if no joy with that let me know the CPU/ mobo and model #s of the DRAM will need timing and/or MC voltage adjustments to try further