I want to upgrade my system but cannot find another CMK16GX5M1B5600Z40 stick in stock locally. My current module supports both EXPO and XMP, while the available CMK16GX5M1B5600C40 appears to have the same capacity, speed, and timings but is labeled for XMP only. My motherboard is an ASRock B650M-HDV/M.2, which supports both memory profiles. Can I use these two sticks together, and would the system run properly with XMP enabled?
2 Answers
The EXPO/XMP label itself is not usually the main concern. Both modules have the same rated speed and primary timings, so there is a reasonable chance they will operate together using XMP or manual settings. However, the motherboard cannot guarantee compatibility just because it supports both profiles. If the mixed pair fails to train or becomes unstable, you may have to disable the profile and use slower default settings.
They will probably work together, especially since the specifications are nearly identical, but mixed memory is never guaranteed. The modules could use different memory chips or have slightly different subtimings, which can cause instability. If they do work, the system will generally run both sticks at the slowest common settings. You may need to test stability or manually configure the timings rather than relying on the profile.
I would have to buy the second stick without being able to test it first, so I may wait for the matching Z40 model to come back in stock.