I upgraded from a 32GB DDR4 kit to a larger-capacity kit with the same advertised speed and model family. My previous dual-stick kit ran at 3200 MHz without problems, but the new memory causes black screens and general instability at that speed. I'm using the same motherboard slots on an MSI X470 Gaming Plus Max with a Ryzen 7 2700. The new kit is Corsair CMK32GX4M2E3200C16, while the previous kit was CMK16GX4M2B3200C16. Lowering the speed to around 2993 MHz seems mostly stable, although the reported memory speed sometimes looks unusual in Task Manager. Is this caused by the newer kit or by limitations of the CPU's memory controller?
2 Answers
This is probably a memory-controller and rank limitation rather than a faulty kit. Zen+ officially supports lower memory speeds as the memory configuration gets more demanding, and higher-capacity DDR4 modules are often dual-rank. That puts more strain on the Ryzen 7 2700 than your older 32GB kit did, even if both kits are rated for 3200 MHz. Try setting the memory manually to 2933 MHz, then 2800 or 2666 MHz if needed. The gaming performance difference should be small.
That behavior is expected when the newer modules place more load on the CPU’s integrated memory controller. The advertised 3200 MHz rating is typically based on motherboard and CPU compatibility, so running at 2933 MHz or slightly lower can be the practical stable setting for this system.
Try downclocking the new kit to 2933 MHz first instead of using 3200 MHz. Older Ryzen processors can be picky with Corsair memory kits, especially when the capacity or memory layout differs from the previous modules. If 2933 MHz is stable, there is likely nothing wrong with the RAM; the system simply cannot maintain the rated overclock with that particular kit and CPU combination.
Could the difference between the two kits be the reason? The previous kit was CMK16GX4M2B3200C16, while the new one is CMK32GX4M2E3200C16.
The new kit is CMK32GX4M2E3200C16. My older kit ran perfectly at 3200 MHz, while the new one seems to work around 2993 MHz, although Task Manager occasionally shows an odd value after changing the speed.