My PC currently has two 8GB XPG Gammix D10 DDR4 sticks installed. I also have two 8GB ADATA XPG Z1 DDR4 sticks from an older computer. Can I install all four sticks together, or could mixing these different kits cause damage, instability, or a noticeable performance drop?
4 Answers
Mixing them won't physically damage your computer or make the sticks harm each other. The main issue is compatibility: they may fail to boot together, or the system may lower the memory speed and use more conservative timings. It's generally safe to try, as long as you're prepared to remove the extra sticks if the system becomes unstable.
Different kits often work together, but matching pairs provide the best chance of stable operation. The result depends on the motherboard, CPU, rated speeds, timings, and memory voltage. If you install all four, test the system with a memory diagnostic tool. If you see crashes or errors, lower the RAM speed manually or revert to the original matched pair.
Using four sticks can put more stress on the CPU's integrated memory controller than using two, so stability is never guaranteed even when the RAM is the same general type. Check the motherboard's supported memory configurations and make sure the sticks are installed in the recommended slots. Physically, though, mixing these DDR4 modules is not inherently dangerous.
The memory will usually run at the slowest kit's speed, and sometimes even lower depending on what the motherboard and CPU's memory controller can handle. For example, pairing 3600 MT/s and 3200 MT/s sticks would typically mean running everything at 3200 MT/s. More total RAM can still be worthwhile despite the lower speed.
If the system refuses to start, just remove the added sticks and try again. Testing is usually harmless, and many mixed configurations work fine once they run at a common lower speed.