Question Gigabyte Z370 Ultra gaming pro not posting if ram is in slots 1 or 3, will post if ram is in 2 or 4 but not run in dual channel.

Jan 13, 2021

I purchased a Gigabyte Z370 Ultra Gaming Pro about 2 years ago and the motherboard manual states to place ram in 1 and 2 or 3 and 4.

However when I did this a few years ago it didnt work but found that placing it in 2 and 4 worked fine and didnt think much more about it as thats the slots I had used for dual channel on all previous motherboards.

However today I noticed that the ram has been running in single channel for I assume the entire time.

When I switched either ram stick to slot 1 or 3 the pc would power up for around 10 seconds, not post, and restart.

I have tried every combination of either 1 stick or 2 sticks. Both sticks work fine either alone or together if they are in slots 2 or 4.

However, if either stick is in 1 or 3, no matter where the other stick is, the computer will not post.

Is there a fix for this issue or has my motherboard been faulty this entire time and I have just realised it.

Thanks for any help you can give


Retired Mod
ALL dual channel aftermarket motherboards sold in the last 10-12 years that have four DIMM slots use the DIMM slots that are located in the 2nd and 4th positions away from the CPU socket as the primary population rule designated slots. There aren't any exceptions to that rule that I've seen and I've looked at the motherboard population rules for practically every motherboard on the market from the last ten years at least, and quite a few more dating back to the change from low density DDR3 to high density DDR3. For all DDR4 dual channel aftermarket boards, FOR SURE, it is without exception the 2nd and 4th slots.

If you have memory that is VALIDATED for use on your motherboard either through the motherboard QVL list or the memory manufacturers validation list (Corsair memory finder, G.Skill memory configurator, Crucial memory advisor, unfortunately, other brands don't have such a list or utility which is why I rarely recommend them for enthusiast systems) and came together in ONE kit, not purchased separately as single sticks or multiple kits, then there is either a problem with the memory, the motherboard, the CPU (Bent pins, user caused damage such as being dropped on a hard surface, thermal fatigue from overclocking, etc.), motherboard standoffs placed in the wrong positions under the motherboard or in some cases even a CPU cooler that is not evenly tightened all the way around (Causing the CPU to "cock" in the socket and lose contact with one or more contact points) or is over tightened (Which can also cause problems).

WHERE did you see that it is not running in dual channel? According to WHAT? Please provide screenshot.

Were these sticks purchased together, in one kit, or were they purchased as individual sticks of the same memory? It's almost impossible to have two compatible sticks running in the correct slots, at the correct (Or any) speed and not be running in dual channel or at the worst, in flex mode with a portion of it running in dual channel when two different sized DIMMs are used.

I think your confusion probably stems from poor information in MOST motherboard manuals regarding WHICH slots are actually the correct slots.

So, starting at your CPU, count over one, two, put a DIMM in the second slot over, and then put a DIMM in the slot that is closest to the edge of the motherboard. Then try it. If you still believe that you are not running in dual channel at that point OR if it will not POST with the DIMMs in those slots, then there is either a motherboard or CPU problem and I'd recommend pulling the CPU and checking for bent pins. Yes, MANY systems run fine for long periods of time with bent pins and are not noticed until some point down the road. Many pins are redundant, and some are only used for specific functions such as some memory operations, or specific segments of the PCIe bus circuit, etc.

If no pins are bent, then I'd start giving the motherboard the stink eye.