I'm using a Gigabyte B450M DS3H motherboard with a Ryzen 5 5600. I have two separate 2x8GB DDR4 kits: an older ADATA XPG Gammix D20 kit and a newer ADATA XPG Spectrix D35G kit. Each kit works normally by itself, and one stick from each kit can also boot. However, installing two D35G sticks plus one D20 stick—or all four sticks together—causes the system not to boot. I'd like to understand whether this is a slot-order, BIOS, speed, or memory-compatibility issue and how to troubleshoot it safely.
3 Answers
Even if the kits have matching capacities and advertised speeds, two separate kits aren’t guaranteed to work together. Their memory chips, timings, or required voltage may differ, and adding more sticks puts extra stress on the Ryzen memory controller. Start with BIOS defaults: clear CMOS, disable XMP/DOCP, and let the RAM run at its standard JEDEC speed. If the system boots, you can try enabling a lower speed manually, such as 2933 or 3000 MT/s, rather than the kits’ full rated profile.
For two sticks, use the motherboard’s recommended paired slots—normally DDR4_2 and DDR4_4, which are usually labeled A2 and B2. For four sticks, populate all four slots, but mixed kits may still fail even with the correct placement. Test each kit alone in A2 first, then test the full set at default settings. If each kit passes alone but the combination fails, the likely issue is compatibility or memory-training limits rather than a dead stick.
Update the motherboard BIOS if it’s behind, since later versions can improve Ryzen 5000 memory compatibility. Also confirm that both kits are DDR4 and compare their rated voltage, frequency, and primary timings. If four sticks remain unstable, the practical solutions are to use only one matched kit or manually configure all four sticks to the slower kit’s settings with a modest speed and possibly slightly relaxed timings.
I cleared the CMOS, but the mixed configurations still behaved inconsistently. One D35G stick in DDR4_4 and one D35G stick in DDR4_2, with a D20 stick in DDR4_1, eventually booted into the BIOS. I know that may not be the recommended layout, so I’m checking the correct slot arrangement before changing settings.