Hey everyone! I'm planning to build a workstation PC primarily for AI workloads (just for fun) and some gaming on the side. Since I'm handling heavy tasks, I aim to max out my RAM at 256GB. Here's what I've got so far: an AMD Ryzen 9950x processor and an MSI MAG X870E Tomahawk WiFi motherboard, along with my existing RTX 4090.
I'm feeling a bit confused about RAM specs and could use your insights:
1. RAM is labeled with numbers like DDR5-5600, DDR5-6000, etc., but it's not clear if that's MHz or MT/s. Is this just marketing fluff, or can I trust the labeling?
2. If we assume it's MHz, I've read that MT/s should be double that number. With my motherboard only supporting a max of 6400 MT/s, does that mean I might be overshooting my RAM specs? Would DDR5-5600 be sufficient for my needs?
3. I've noticed there's a tradeoff between lower CAS latency (CL) and higher frequencies (if it's MHz). I've found G.SKILL Ripjaws S5 Series (CL-36, DDR5-6400), which is XMP only. Can I use this reliably with AMD at 6400MHz, or why is there an equivalent AMD EXPO module only at DDR5-6000? Thanks for any help!
1 Answer
Alright, so let's break this down a bit. When it comes to DDR RAM, 'DDR' stands for double data rate. For example, DDR5-6000 actually operates at 3000MHz. The sweet spot for Zen 4 and 5 CPUs is around 6000 with a CAS latency of 30. Just to clarify, above 3000MHz, the memory controller doesn’t run in 1:1 mode and can add some complications for overclocking. If you're going for 6400 CL36, just know it might use less desirable chips compared to 6000 CL30, which often have better performance.
That’s good to know! But I’ve been looking for 64GB CL30 modules for my build and can’t find any. 4x64GB is a must for 256GB.