DDR5‑6000 CL26: instability on one module. Stable at 5800 MHz CL26

[Vladislav]

Hello,
I’m experiencing an issue with my G. Skill DDR5 me mory kit and would appreciate your technical advic e before proceeding with an RMA.

System configuration:

• Memory: G. Skill Trident Z5 Royal Neo F5-6000J2636H32GX2-TR5NS DDR5‑6000 CL26 (2?32 GB)
• Motherboard: MSI MPG X870E CARBON WIFI
• CPU: AMD Ryzen 9 9950X3D
• BIOS: 7E49v1A70 (2025-10-14)
• Memory slots: A2/B2 (recommended for dual‑channel)
  
  Problem description:
• At the stock EXPO profile (6000 MHz, CL26‑36‑36‑96 ), one module consistently fails memtest86+ v8.0 (errors appear within 1 passes).
• The second module works perfectly at 6000 MHz CL26 .
• Stability achieved in two scenarios:
  1. 5800 MHz + original timings (CL26‑36‑36‑96);
  2. 6000 MHz + slightly relaxed timings (CL28‑36‑36‑96).
     
     Test details:
  3. memtest86+ v6.00 (3+ passes, no errors at 5800 MHz/6000 MHz with adjusted timings).
  4. Memory temperature during testing: 55 -65?C (case: Lian Li O11 Dynamic EVO XL, 6?140 mm fans) .
  5. DRAM Voltage: 1.45 V (default for EXPO).
     
     What I’ve tried:
  6. Module reseating and slot swapping (A2↔B2).
  7. Clearing CMOS and resetting BIOS.
  8. Verifying serial numbers and registration (modules registered on G. Skill website).
  9. Individual module testing: I tested each module separately in slot A2. The results confirmed:
     • Module 1 (serial № 25344742059) works stably at 6000 MHz CL26.
     • Module 2 (serial № 25344742060) consistently fails memtest86+ at 6000 MHz CL26, but passes tests at 5800 MHz CL26 or 6000 MHz CL28 .
       
       Questions:
     • Is this behavior indicative of a hardware defect, or are there further tuning options to explore?
  10. Attachments (available upon request):
  11. BIOS screenshots (memory settings).
  12. memtest86+ logs.
  13. Photos of module serial numbers
  14. Thank you for your time and support. I look forwar d to your recommendations.
      
      Best regards,
      Vladislav

[GSKILL TECH]

If one memory module performs differently than the other, replacement will be necessary. Please submit the RMA request form online to initiate the warranty exchange process:

https://www.gskill.com/rma-policy

Thank you