Error C5/0d indicates a specific issue requiring attention.
Error C5/0d indicates a specific issue requiring attention.
Hello, please accept my apologies if this seems straightforward. I recently purchased a new system and case. Once I finished assembling the PC, I encountered an issue where the system detected a new CPU. After checking the BIOS, I resolved it, but later faced booting problems with error code "C5/0d". Initially, removing all RAMs and then putting one in worked, followed by the full set. After rearranging fans and placing RAMs correctly, the PC started again. However, after switching some fans, the same error reappeared. I tried inserting RAM one at a time in the second slot, then all at once in the first, but the mainboard still reported "C5/0d". Is it possible the RAM slots are faulty? I just ordered a replacement and wanted to avoid extra stress during build. Note: My GPU isn’t fitting properly because the case obstructs its rear. Should I adjust the BIOS settings after swapping the CPU? Also, is there anything specific I should do in the BIOS now?
The issue is tied to your Corsair memory kit's model. Check if it appears in the motherboard's QVL. Monitor for any Q-LED changes when you see Q-Code 0d. Confirm the BIOS version currently installed. It's possible one or more of the four RAM sticks are defective from Corsair production. Determine whether the problem lies with the CPU, motherboard, or RAM. Testing components without a proper diagnosis can be costly. Avoid using generic parts lists for PCs.
Thank you for your response and for clarifying your situation: The model code for my memory kit (Dominator Platinum RGB 4x 32GB / DDR5 / 5600MHz) is CMT64GX5M2X5600C40. The kit was included in the QVL specifications on the motherboard. Yes, the orange LED indicating "DRAM" is active. My BIOS version is 0805, and I reset it to the default settings just to ensure stability. I disabled XMP, which means the RAM operates at its standard speed rather than the higher one. This could affect compatibility with the QVL list—some models might not show all devices if they run slower. I confirmed with four RAM sticks installed in different slots; the PC started up fine as long as none were used in slot 1. It seems the issue isn’t with the CPU, but rather with the RAM configuration or slot selection. You mentioned testing all four sticks and only one causes a boot error when placed in slot 1. That suggests the problem is likely related to the physical placement or slot compatibility. Your clarification about the QVL list is helpful; it confirms that my setup should work if the RAM is properly seated. Thank you for your patience and for providing such detailed information.
For those who could encounter this message, I swapped out the mainboard and still faced the same problem. It seems there might be a problem with the memory controller on the CPU. I plan to replace the CPU and will provide an update once it’s done. I’ve seen some discussions about this error, and others reported fixing it after swapping the CPU. The CPU itself shows no signs of damage, and the pins on the AM5 boards also appear intact.
@DoNotDropIt Apologies, I didn't manage to reply. ASUS only checked the memory kit with a 2x DIMM setup (32GB in pairs). They haven't confirmed compatibility with 4x DIMMs. Also, using more modules increases stress on the Integrated Memory Controller. Running 2x modules tends to perform better than 4x, especially at higher speeds. (For example, 2x DDR5-5600 sticks are simpler than 4x or DDR5-5600.) If XMP/XMP/EXPO is turned off, the RAM will default to JEDEC fail-safe settings (possibly DDR5-4400). Yes, even PC memory must meet certain specs. XMP adds an overclock profile based on manufacturer-programmed data. You can't completely eliminate the risk of a faulty CPU, especially if Slot #1 is suspected. As noted, the IMC is inside the CPU, so a bad CPU could be the issue if Slot #1 is defective. The motherboard has already been replaced, yet the problem persists, suggesting the board isn't the main cause. Have you tried using just 2x DIMMs instead of all 4x at once? According to the manual, ASUS recommends: Slot #2 for one DIMM, Slot #2 and #4 for two DIMMs, and Slots #1-4 for four DIMMs.
Hey no worries, thank you for the replies anyway. I also called Asus and AMD tech support and asked if there were known issues and what their assumption on my issue is. The Asus support wasn't too helpfull, but I think I just tried more or less everything you could try, besides replacing the CPU. So yes I tried to boot the PC only with 2 RAM and with 4. As long I don't use RAM slot 1 the PC boots. So I could use just 1 RAM in either slot 2,3 or slot 4, or two RAMs in (2/3/4). What confused me is that I also was able to boot the PC a couple of times when all 4 RAM sticks were installed. But I didn't tried since then. ASUS and AMD said there should be no issues with just booting the PC in either of the RAM slots. They also said, it's unlikley the motherboard or CPU are faulty but not impossible. AMD said it could also be an BIOS issue, but if it were an BIOS issue I would probably find a couple of people complaining about similar issues with the motherboard/CPU/RAM. My setup isn't special by any means. I'm sure many other people have the same hardware. Not being able to find forum posts on that issue let me to believe it might be indeed a harware issue. So I basically replaced everyhing but the CPU and PSU. I even replaced the PSU cables just in case. So after replacing the motherboard and getting the same issue I just hope it's the CPU. Firday I get the replacment CPU and then I will know. If that does not help, I will be very confused. Even if the board wasn't tested with 4 RAM modules, There are for sure many more people who would also use 4 RAM modules and would complain about similar issues. For me it's really telling not being able to use the first RAM slot, there might be something wrong in general. The recommendation of AMD was to try to replacing the CPU with another one (AM5), and maybe replacing the RAM modules. For testing puposes I could try to plug in my brothers RAM and CPU, but for now the new CPU will be faster at my home, than my brothers. I did not make any changes in the BIOS settings, I didn't want to play around until I could verify the system is stable with default settings. AMD told me that AM5 should have XMP enabled by default, however for my board XMP was turned off with the default settings, so I didn't even try to turn them on. I highly doubt the RAM slot 1 would work after I would turn on XMP. I mean I could just use 2 of my RAM and it would probably work just fine, or I would get issues along the way after weeks or months using the PC. If it's a CPU issue I would be very upset finding out weeks or months later. Now I can just return the CPU to the vencor (Amazon) and just order a new one withing 30 days. As soon my PC runs without issues I won't touch it for years, maybe once a year to clean the dust. Right now it's the best time for me to just make sure it runs as it supposed to run. If for some reason replacing the CPU does not change anything. I probably will replace the motherboard with another one (different model) and just in case a new PSU. Then I basically replaced the entire PC. I'm just thinking about ordering a 2nd PSU just in case, but I'm very confident it's not the PSU. I will give an update after I replaced the CPU.
I made another change. I inserted one RAM into slot 2 (A2), it worked fine, then I put one in slot 3 (B1) but it didn't start up at first. After a short wait it did boot. Then I installed a RAM into slot 4 (B2) and it also failed initially. I waited a few minutes and it finally started. Next I tried slot 1 (A1) again and it showed error 15 once more. After about two minutes it worked. I restarted the PC and it displayed error 0D, which prevented it from booting again. Now I'm curious what's going on. Am I using the correct GPU cable? I checked a video online where someone fixed error 0D by swapping out the GPU power cable. I replaced it and the PC started up. That means the original cable might have been the problem. I was using a different (Fasgear PCIe 5.0) GPU cable instead of the one from Corsair PSU, which supports 3090/4080/4090 models. Using the wrong cable could cause these issues. So my confusion comes from testing multiple times with different RAM slots and cables. I'm still unsure if the CPU is the issue or if the RAM setup needs adjustment. I plan to replace the CPU and see if it resolves this problem.
Updated: I swapped the CPU (same model or new one) but it still didn't function. I also swapped in a different RAM (Kingston), yet nothing changed. All other components except the PSU remain untouched. The system won't boot when using RAM slot 1 (A1); it should work otherwise. I reached out to ASUS, who promised a follow-up call tomorrow after their headquarters contacted them. I slightly adjusted the AIO pump, as some suggested that might help. My RAM slots are correctly installed. I also ordered another ASUS mainboard of the same type, but repeatedly trying the same steps without success feels frustrating (though it seems some people win in lotteries—possibly due to defective boards). I purchased an MSI mainboard. It’s possible I could run the PC with all four RAM slots active, but I can't overlook the fact that thousands of USD/EUR are being spent on a machine that keeps failing. Using slot 1 (A1) alone triggers error C5 with a DRAM LED. Slot 3 (B1) alone also causes the same error (previously it didn’t). Combining slots 1 (A1) and 3 (B1) doesn’t resolve the issue. Combining slots 1 (A1) and 4 (B2) also fails, resulting in the same error. I’m aware you should use only RAM slot 2 (A2) when using a single module. You should use slot 2 (A2) and 4 (B2) if you have two modules. I also understand you should be able to configure any setup, even if it’s not ideal.
Updates: After fitting all four RAM units the system starts after a brief delay for RAM setup. Restarting triggers the 0d message. Taking out any RAM unit allows the PC to launch normally. Adding the fourth RAM after that leads to successful boot. Repeated restarts consistently show the 0d error. Clearing CMOS brings the PC into BIOS, requiring a full installation process. Each time I remove a module it boots again with 0d. Swapping the motherboard or CPU stops booting with four RAMs.