Question Half of the motherboards RAM slots do not work

Jul 13, 2019
Hello everyone. I am posting about an issue that I have been trying to solve for almost two years and cannot fix. I am hoping someone can either help me fix the issue or confirm that it just might be that my motherboard is broken.

The issue is that only half of my RAM slots work. The motherboard is an Intel DX79TO. Four of the eight slots do not function at all regardless of what type of DDR3 RAM goes in the slots. I have ten sticks of RAM in total; four sticks of Samsung 1333MHz, four sticks of ADATA 1333MHz, and two sticks of HyperX 1866MHz. All of the sticks function in any machine and they work together just fine (i've mixed all 3 types together on one side of my motherboard and they all worked fine), but on my motherboard, any time I put one stick of RAM in the right side of the board, the machine gives three, one second beeps and repeats until the computer is shut off; no display is shown. I have RAM in DIMM slots 1, 5, 2, and 6 while the empty slots are 8, 4, 7, and 3. Slots 1, 2, 3, and 4 are blue slots and 5, 6, 7, and 8 are black. The manual for the board says if I have four sticks or less, I should only use the blue slots. I tried this and put them all in the black slots, but both configurations did not work. The computer will only boot if there is no RAM in slots 8, 4, 7, and 3, which are the slots to the right of the CPU. I can have any type of RAM at any speed in the left side and it will always work, but once the right side has one stick in any slot, I get a memory error.

I have tried:
Cleaning the sticks & slots with rubbing alcohol,
Tested the sticks in different machines,
Used all different types of RAM in all slots,
Resetting my BIOS configuration (BIOS Jumper Pins and Battery),
Tried only booting with RAM in the right side,
Changing out the CPU.

My Setup:
Motherboard: Intel DX79TO - (Motherboard Manual with pictures on page 12: )
CPU: Intel i7-3930K @ 4.2GHz
RAM: 4x4 Samsung 1333MHz (1.5V)
GPU: Geforce GTX 1070
PSU: Cougar CMX 1000W
OS: Windows 10 Pro - 64bit

If anyone knows why the whole right side might not be working and can provide me with a solution, that would be amazing.
Thank you,
Jul 13, 2019
The "solution" would presumably be a replacement motherboard.
If all the settings in the BIOS point to it working, and it does not....then the board is physically broken.
That's unfortunate. Something I forgot to mention though was that I used to be able to use two sticks in slots 8 and 4 and get triple channel, but didn't have any other sticks at the time to get quad channel. If everything I stated points to the motherboard just being broken, that is a waste of $80 on RAM for a motherboard that won't even work. My computer still functions without those 4 slots being occupied, but a higher RAM count would be nice.