1st RAM slot not working. (Gigabyte GA-78LMT-S2P)

[SynX]

Hi recently I got a  Gigabyte GA-78LMT-S2P as an exchange for my blown up MSI motherboard.
The problem I have is the motherboard that I own (GA-78LMT-S2P) does find both RAM modules installed, but only uses the memory from 1 module. (Im making it sound complicated I know sorry).
I have a Kingston DDR3 2x4GB 1600Mhz RAMs, the system only boots if the RAM stick is in the 3rd slot (furthest one away from CPU socket), otherwise it does not boot. (Bios labels them 1 and 3 for some reason.)
I am running a 64bit Windows 10 which shows that there is 8GB of RAM installed but 4GB is reserved for hardware.
I tried everything users with this issue recommended starting with changing RAM on boot, to changing directories. I have recently updated the BIOS with the latest version (F4B) and it did not change anything the RAM in the first slot is not used at all.
Also the AMD CPU has been overclocked from 3.5Ghz to 3.8Ghz, I don't know if the overclocking would mess anything up with the RAM. I had a similar issue with my previous MSI board, but in there, there was a case of dust in one of the sockets, unlike here the motherboard is around 2 weeks old.

The full system specs:
AMD FX-8320
Gigabyte GA-78LMT-S2P
Kingston DDR3 2x4GB 1600Mhz
MSI GTX970
Windows 10 64bit
F4B Bios Version.

[AgentFXA]

Your mobo, even at rev 5.0, does not support the FX-8320 CPU - only the 8320E which is slower clocked.

[SynX]

Your mobo, even at rev 5.0, does not support the FX-8320 CPU - only the 8320E which is slower clocked.

So are you saying the 1st RAM slot is picked up due to a unsupported CPU installed?

[shadowsports]

He is saying that could definitely be a contributing factor. 

You are running an unsupported CPU which may or may not be properly detected (even with a newer BIOS). 
You are over clocking, which could further introduce a compatibility issue.

Even though this board has a south bridge, the memory interface is still in the CPU. 

Have you tried running the config without an over clock?

What is the model of your RAM - KHX1600C9D3K3/12GX is tested with your board.

There just aren't any guarantees when using unsupported hardware + an over clock. 

[SynX]

He is saying that could definitely be a contributing factor. 

You are running an unsupported CPU which may or may not be properly detected (even with a newer BIOS). 
You are over clocking, which could further introduce a compatibility issue.

Even though this board has a south bridge, the memory interface is still in the CPU. 

Have you tried running the config without an over clock?

What is the model of your RAM - KHX1600C9D3K3/12GX is tested with your board.

There just aren't any guarantees when using unsupported hardware + an over clock.

I have tried running the system without the overclocked applied, but something odd I noticed was the default CPU speed was only 2.9Ghz not AMDs default speed which is 3.5GHz.
If anyone wandered what my previous motherboard was: MSI 760GMA-P34
The ram I use is a: Kingston KVR16N11S8/4 1.5v 2x4GB.

[AgentFXA]

Again,
3.5ghz is the default speed of the FX-8320 which is not supported on your mobo - fastest FX-8.... speed you can do is 3.3ghz with an FX-8370E

go with an old FX-4350 for highest speed supported on your board

[SynX]

Hello. I have just bought and installed a brand new Gigabyte 78LMT-USB3 Ver 6. and this time my RAM has gone down to 3.89 usable from 8GB installed, but bios only detects 4096 MB. I am still using the same RAM and the same CPU. Do you guys know what exactly this could be. I have also installed the RAM into the second and forth slot (grey) on my motherboard since this is what the manual said to do.

[shadowsports]

Hello. I have just bought and installed a brand new Gigabyte 78LMT-USB3 Ver 6. and this time my RAM has gone down to 3.89 usable from 8GB installed, but bios only detects 4096 MB. I am still using the same RAM and the same CPU. Do you guys know what exactly this could be. I have also installed the RAM into the second and forth slot (grey) on my motherboard since this is what the manual said to do.

So you have solved the MB / CPU compatibility issue.  The new board supports 1066/1333Mhz ram and some 1600Mhz with over clock.  All of the modules listed on the QVL are DS, yours is SS.  Strongly suggest using ram from the QVL.  You can try manual configuration but this is ultimately like gambling.  What does this mean?  The JDEC profiles supported by your memory are not what your BIOS is expecting.  Manual configuration is possible but not guaranteed. 

Your RAM:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiOkLX2p8jTAhVN-mMKHQ4lANEQFggnMAA&url=http%3A%2F%2Fwww.kingston.com%2Fdatasheets%2Fkvr16n11s8_4.pdf&usg=AFQjCNEial1CITXzlfNvVcZurC2QWo4vbQ&sig2=du4D3Qql6A08kGfg_Q62LA

QVL RAM:

http://download.gigabyte.us/FileList/Memory/mb_memory_ga-78lmt-usb3.pdf   

[AgentFXA]

OP might try his Kingston ram @1333 speed - Kingston is only QVL listed once @1333
His board seems to hate Kingston ram...

[SynX]

Right, I have downclocked the RAM to 1333, and nothing has changed. still 3.96GB usable. I was thinking will disabled On board graphics chip still reserve some RAM?

[SynX]

Okay I have found a fix. On the 78LMT-USB3 I have set the RAM speed to 3200MHZ which messed up the bios and it has showed up a error message saying "failed to boot due to unsupported ram speed", i have then turned the system off and cleared CMOS using the battery, and then inserted the RAM sticks into the slot, 1 and 3 (1st from right grey and 1st from right black), then went into bios and downclocked the RAM from 1600MHz to 1333MHz, and booted the system. Then Windows, CPU-Z and Bios all detected 8GB installed and usable. Thank you for trying to resolve the problem and appreciate it. But now you guys know what it could cause the problem.

[shadowsports]

A few others have complained about something similar to this.  A condition where their memory is properly detected, but only as single channel instead of dual.  It seems to happen when using unsupported RAM and in other instances when over clocking.  I did some reading and found others on web complaining of the "hardware reserved" issue.  A small percentage of people where using a 32bit OS, thus only getting 4GB of addressable memory with the remaining being reserved.  The others were attributed to incorrect timings.  In some cases, a newer BIOS resolved, others by using manual settings, and others again (like you), by forcing the BIOS to "let go" of whatever was keeping it from detecting the full amount of installed RAM and configuring it as dual channel with 2 or more slots populated.  These types of issues are the hardest to solve since no one solution seems to fix the behavior for everyone consistently. In any event, good work solving the problem.  Since you are down clocking faster RAM, you have better odds of remaining stable.  If you were over clocking you might be a restart away from another failure.  Hope things remain stable for you.

[AgentFXA]

Okay I have found a fix. On the 78LMT-USB3 I have set the RAM speed to 3200MHZ which messed up the bios........

If we had a crystal ball showing us the untold things ... then it would be much easier to help people