I'm using a Gigabyte B450M DS3H motherboard with a Ryzen 5 5600. I previously had an ADATA XPG Gammix D20 2x8GB kit and recently bought an ADATA XPG Spectrix D35G 2x8GB kit. Each 16GB kit works normally by itself, and one stick from each kit can also boot. However, installing both complete kits causes the system not to boot. Two D35G sticks plus one D20 stick also fails. I cleared the CMOS, and one unusual arrangement—two D35G sticks in DDR4_4 and DDR4_2, with one D20 stick in DDR4_1—managed to boot into the BIOS. What settings and slot arrangement should I use, and is mixing these kits likely to work reliably?
3 Answers
Clear the CMOS properly, boot with one known-good kit, and confirm the BIOS is running at safe defaults. Then power down and install the other kit. If it still fails at stock settings, the two kits likely have incompatible memory chips or timings. In that case, the dependable fix is to use one matched 2x8GB or 4x8GB kit rather than combining separate kits. Afterward, test with a memory diagnostic tool to check for errors.
Mixed memory kits aren’t guaranteed to work together, even when the kits have the same capacity and advertised speed. Start with BIOS defaults: disable XMP/DOCP, set the memory speed to Auto or a conservative value such as 2133/2400 MT/s, and let the board retrain the memory. Once it boots reliably, you can gradually test higher speeds. Also make sure the BIOS is reasonably up to date for the Ryzen 5 5600.
For two sticks, use the motherboard’s recommended paired slots, normally DDR4_2 and DDR4_4—the second and fourth slots away from the CPU, according to the board manual. With four sticks, populate all slots, but don’t assume the system will accept the kits at their rated settings. If you use three sticks temporarily, that is an unusual configuration and may run in a less optimal memory mode; it’s useful for troubleshooting but not the preferred final setup.
Both kits work by themselves, but combining them only works in one odd arrangement. I’ll leave the memory settings at default and test stability before trying a faster profile.