I currently have 16GB of DDR4-2133 memory installed in a PC with an ASUS Prime Z370-A motherboard. I want to upgrade to 32GB, but I can't find another matching 2133MHz kit. Would adding a 16GB (2x8GB) DDR4-3200 CL16 kit work alongside my existing RAM? I understand the system would probably run all the memory at the slower speed, but could mixing these kits cause instability or prevent the computer from booting?
3 Answers
A matched set of two 16GB modules is the safer option and will usually give you fewer compatibility problems than combining two unrelated kits. If you can’t find matching 2133MHz memory, replacing the current RAM with a tested 32GB kit is preferable. Used memory may also be worth checking, provided the specifications match.
Check the motherboard’s memory compatibility list and compare the exact specifications of your existing RAM with the new kit. The proposed kit is rated for 3200MHz at CL16 and 1.35V, but it may need to run at the old modules’ settings when mixed. XMP may not work reliably, so you might have to configure the speed and timings manually or leave everything at the default setting.
It shouldn’t damage anything, and the faster kit will generally run at the slower kit’s speed and timings. However, mixing separate kits isn’t guaranteed to work. The board might fail to boot or become unstable, especially if the old and new modules use different timings or voltages. If that happens, remove the new kit and look for a matched 32GB kit instead. The first boot can also take a minute or two while the motherboard trains the memory.
I wasn’t aware there were compatibility lists for specific motherboards, so I’ll check those and compare the details before buying anything.