For the 9950X3D, I've had excellent results with G.Skill Trident Z5 DDR5-6000 CL30. The sweet spot for Zen 5 seems to be 6000MT/s with a 1:1 FCLK ratio (so memory controller runs at 3000MHz). Higher speeds often force the infinity fabric to run decoupled, which can actually hurt performance despite the higher MT/s numbers. Make sure to get a kit with decent primary timings (CL30 or better) as that makes a significant difference with 3D V-Cache.

> The sweet spot for Zen 5 seems to be 6000MT/s Spot on with the 6000MT/s target, but honestly, trying to hit that with a 128GB kit is a whole different beast. Pushing those high-density 64GB sticks is basically the ultimate stress test for the memory controller on these chips - it can get REAL finicky. From a budget perspective, unless you're doing heavy-duty workstation stuff, that extra capacity is a huge price premium for potentially less stability. Tbh, if you do go for 128GB, focus more on finding a kit that's on your motherboard's QVL list rather than chasing the absolute lowest timings. It'll save you so much DRAM-related frustration and money in the long run. Sometimes "good enough" timings are just better for stability when you're maxing out the capacity like that.