Added 8GB of Ram to 4GB install and system info shows only 4GB usable

[robbydobbs]

I have a Asus P7P55D-E-LX with the Corsair XMS 4GB kit 2x2GB ram installed. I upgraded my ram and added CRUCIAL 8GB 4X2 D3 1600 DIMM CL9. When I boot up my system it shows 12GB of ram but only 4GB usable. I also went back and changed the slots the ram was in I moved the crucial ram to the first two slots and took out the original Corsair I had in it and when I rebooted it still stated that there was the crucial 8GB in the computer but only 4GB usable. For some reason, I can only use 4GB of ram no matter how much is in the computer. The motherboard allows up to 16mb ram. What can I do to be able to use all the ram in the computer.

 

[Tradesman1]

Couple of things, if a 32bit system 4GB is max, if you have a 64bit OS then the new DRAM doesn't sound like it wants to play with the old, or may simply not be compatible - with the P55 chipset would almost guess your new DRAM uses high density memory chips and aren't compatible with the mobo chipset

 

[robbydobbs]

I went to the Crucial website and put in the make and model of my motherboard and it stated that the memory I purchased was compatible with the motherboard. When I put just the 8GB of Crucial memory in the computer by itself, it still only shows 4GB usable. I don't understand everything there is to know about memory and motherboards but I'm trying to learn. If my motherboard says it supports up to 16gb of memory, and the memory I had in there was (4GB)DDR3 1600, than why wouldn't it recognize the 8GB of DDR3 1600 regardless of the manufacturer.

 

[McHenryB]

So, are you running a 64-bit operating system?

 

[robbydobbs]

64-bit operating system Windows 8.1

 

[Tradesman1]

Both sticks work by themselves?

 

[robbydobbs]

yes, but the 8GB shows 8GB installed but only 4GB usable. When I put the other 4GB in with the 8GB, it shows the 12GB installed but only 4GB usable. So it doesn't matter how much memory I put in the on the motherboard, it only shows 4GB usable.

 

[Tradesman1]

Try with 2 sticks and raise the DRAM voltage + 0.06 and the QPI/VTT voltage + 0.06

 

[robbydobbs]

how do i raise the DRAM voltage? Do I do that in the bios?

 

[McHenryB]

Check in msconfig that a maximum RAM value hasn't been set.

 

[everseeker]

Check in msconfig that a maximum RAM value hasn't been set.

Um How?

Never saw anything like that in MSConfig
Had not looked closely in a while (That was not it though)
Turns out, My CPU was actually REALLY faulty. It could only "see" half of the installed memory (Dual Channel... could only see one side)