Question CPU debug light turns on with 2 RAM sticks installed ?

[Freeze Aim]

So, I just finished building my PC, but as the title says, I get the debug light on when two ram sticks are installed.

What is odd is that initially, when I first started up the finished build, it all worked dandy, but after changing XMP profile, rebooting, and getting into bios again, the pc suddenly froze, and a restart was required. After that, I’m in a boot loop whenever two ram sticks are in. The BIOS automatically CMOS resetted itself once I tried with only one RAM stick…

I have tried changing RAM voltages up to 1.35v. Changed SoC voltage to 1.1v. Tried the RAM sticks separately on both DIMM 1 and 2, and no issues with the RAM sticks. However, it did not work in DIMM 3 and 4, but unsure if that’s by design. Tried reflashing the BIOS, no success either. I’m out of ideas and help is appreciated.

Specs:
Mobo: MSI MPG B550 Gaming Plus
CPU: Ryzen 5 5600
GPU: Asus Strix Force RTX 2080
RAM: Corsair Vengeance LPX (2 x16GB) @3200Mhz
PSU: Corsair CX650m 650W

 

[Ralston18]

This motherboard?

https://download.msi.com/archive/mnu_exe/mb/MPGB550GAMINGPLUS.pdf

[Verify that I found the applicable User Guide.]

From the User Guide, physically numbered Page 15:

"Always insert memory modules in the DIMMA2 slot first."

Double check that the installed RAM is supported, that the correct RAM slots are being used, and that RAM is installed in the proper order.

Specifically DIMMA2 slot first.

 

[Freeze Aim]

This motherboard?

https://download.msi.com/archive/mnu_exe/mb/MPGB550GAMINGPLUS.pdf

[Verify that I found the applicable User Guide.]

From the User Guide, physically numbered Page 15:

"Always insert memory modules in the DIMMA2 slot first."

Double check that the installed RAM is supported, that the correct RAM slots are being used, and that RAM is installed in the proper order.

Specifically DIMMA2 slot first.

Indeed it's the correct user guide. And indeed I inserted into DIMMA2 first. I have tried all slots with a single stick, and every single slot works except for DIMMB2, though the BIOS of course warns me not to put my RAM stick into DIMMA1 or DIMMB1, but it still boots. Only DIMMB2 does not boot at all, and I'm stuck in a loop.

The RAM is also supported, as I can clock it and boot normally with a single stick. Moreover, as I mentioned previously, both RAM sticks worked, but only after enabling XMP profile (without any OS installed) do I get stuck in a boot loop. I'm unsure why. What's most unreasonable is that it did work before, during the first boot after upgrade. It worked without any issues, as I browsed around the BIOS settings.

 

[Ralston18]

Running out of ideas....

You mentioned "TThe BIOS automatically CMOS resetted itself once I tried with only one RAM stick."

Try clearing CMOS per the JBAT1 procedure on Page 25.

No harm in also trying a new/fresh battery. Just as a matter of elimination.

 

[Freeze Aim]

Running out of ideas....

You mentioned "TThe BIOS automatically CMOS resetted itself once I tried with only one RAM stick."

Try clearing CMOS per the JBAT1 procedure on Page 25.

No harm in also trying a new/fresh battery. Just as a matter of elimination.

I tried resetting the CMOS with a screwdriver via the JBAT1, as I don't have that jumper plastic thingy, but I'm unsure if it was successful.

About changing the CMOS battery, do you really think it would work? I'm thinking maybe I got a defect MB, but then again, why did it work in the beginning?

Additionally, DIMMA1 and DIMMB1 work separately; that is when trying only one stick. However, when trying with a dual channel, it also results in a boot loop, which is very odd...

 

[Ralston18]

Will a new CMOS battery work? Fair question - no way (full disclosure) to know. On the other hand replacing the battery is usually easy to do so worth the try. If the problem continues: "no harm, no foul".

The screwdriver reset is commonly used. However, one must be careful when doing so. Not always sure the the screwdrive maintains the full connectivity required for the reset. Look around: check other cards and computers if possible. Find a jumper to use.

As for a defective MB - not at all uncommon for motherboards etc. to work at first. Then after a few power on/off some component fails.

Lastly, after reading back: Did the RAM modules come from a kit intended for dual channel use?

And DIMMB2 seems to be at the root of the problems - correct?

Use a bright flashlight to inspect the slot. Any signs of debris or damage?

 

[Freeze Aim]

The screwdriver reset is commonly used. However, one must be careful when doing so. Not always sure the the screwdrive maintains the full connectivity required for the reset. Look around: check other cards and computers if possible. Find a jumper to use.

There is no jumper at all to be found. I don't understand why that is not included... It's a tiny plastic thing, like how more expensive could it be?

Lastly, after reading back: Did the RAM modules come from a kit intended for dual channel use?

Yes, they are twins. 2x16 gb sticks, meant to be used together.

And DIMMB2 seems to be at the root of the problems - correct?

That seems to be the case; however, running dual channel with DIMMA1 and DIMMB1 doesn't work either. I'm completely lost.

Use a bright flashlight to inspect the slot. Any signs of debris or damage?

I'll check that as soon as I can. But I'm inclined to believe there is no damage.

I forgot to mention that I also have checked for any CPU pins and if they are bent. They are as new as can be. The PC runs completely fine on that single stick as well. Games are running fine, etc.

 

[Ralston18]

What was changed in the XMP profile?

 

[Freeze Aim]

What was changed in the XMP profile?

Enabling full speed of the ram, i.e setting RAM speed to 3200 Mhz.

 

[Freeze Aim]

It seems like the best action to do now is to RMA it?