I recently upgraded my RAM from 16GB to 32GB by adding two more sticks. Initially, I had DIMMs in slots 2 and 4, and after installing the new sticks, I placed them in slots 1 and 3. To my surprise, after switching the configuration so the new sticks occupy slots 1 and 2 while the old sticks are in slots 3 and 4, my RAM speed doubled from 2000 MT/s to 4000 MT/s. I'm really curious about why this happened. Wouldn't having the same sticks in dual channel increase the speed instead? How did swapping them around make such a noticeable difference? By the way, I don't have XMP enabled on my motherboard. Thanks, Lenovo!
4 Answers
Your RAM slots 1 and 2 are on the same channel (Channel A) and slots 3 and 4 are on Channel B. Since modern memory controllers can optimize performance by training each channel independently, placing matched sticks in each channel like you did usually provides better stability and performance. It sounds like your CPU wasn’t happy with how the memory was mixed initially, so it clocked everything down to the lowest speed. Looks like your rearrangement helped it perform at its best!
Originally, you had both old and new sticks mixed across the channels. Now that each channel has either all new or all old, your setup can sometimes hit a wider tolerance margin, improving stability and speed. It’s often a good idea to experiment with RAM placement if you’re having issues, as it can yield surprising results—even with just two sticks! I once had a PC using 4 DDR3 sticks that only worked correctly in one specific arrangement.
I’d consult Lenovo about that; it’s a bit baffling, to be honest. They might have insights on your specific model’s behavior with RAM configurations.
It’s interesting, but some people have experienced issues with configurations using four 8GB sticks. I’ve seen fewer problems with setups using two 16GB sticks instead. It seems that the way memory controllers work can really affect performance, especially when mixing kits.
I found that strange too! I thought I had positioned the new and old sticks together, but I guess each motherboard is different.