Which RAM is better for 9800X3D: CL30 6000MHz or CL32 6400MHz?

It's generally better to go with the 6000MHz CL30 RAM since the 9800X3D can handle that speed easily. While it’s rated for 5600MT/s, most users find they can reach 6000MT/s without issue. Just keep in mind, going for speeds higher than that might lead to some performance losses unless you overclock manually. If you're tinkering with manual settings, 6400MT/s is doable too, but it can get a bit complex!

6000MHz CL30 is a sweet spot! It allows you to run the RAM controller in sync without needing to lower its speed, which keeps performance up. This RAM spec is pretty inexpensive and widely available, making it a strong choice without requiring much manual tuning.

The X3D chips are fantastic for gaming because their large cache minimizes the performance hit from slower RAM. So, in gaming scenarios, you probably won't notice much difference between the two RAMs. It's more about the overall system performance rather than just RAM speed!

If you have quality RAM sticks that support manual overclocking, then aiming for Hynix chips is a great idea. But if you're more about a set-it-and-forget-it approach, the speed and latency ratings alone should suffice. And don't forget to look into reducing your EXPO voltages; it helps with heat and power consumption!

The importance of infinity fabric hasn't been mentioned yet, and that’s crucial to understand! If your CPU can maintain an IF speed of 2133 with the 6400MHz kit, then you'll see better performance. Just an FYI: making your CPU handle these speeds can sometimes require higher voltages, which might not be ideal for longevity.