Compare G.Skill F4-4000C15Q-32GTZR and G.Skill F4-3800C14Q-32GTZN models for the 5900X.
Compare G.Skill F4-4000C15Q-32GTZR and G.Skill F4-3800C14Q-32GTZN models for the 5900X.
What do you believe about choosing the best kit for maximum performance with the 5900X? F4-4000C15Q-32GTZR and F4-3800C14Q-32GTZN both offer 32GB storage, but differ in speed and features. Are you sure they share the same Samsung B-Die chip? Your opinion matters!
DDR4-3800 CL14 resembles Samsung B-Die, while DDR4-4000 CL15 could be Samsung D-Die or Hynix. Using simple calculations, the latency for DDR4-3800 CL14 is about 7.5 nanoseconds, and for DDR4-4000 CL15 it's roughly 7.37 nanoseconds.
AMD describes the three clock domains as maintaining a perfect 1:1:1 sync, meaning the DRAM SDR clock matches uclk and fclk—such as in DDR4-3600 where the memory real clock, uclk, and fclk operate at 1800 MHz. The company also increased the fclk upper limit to 2000 MHz with Zen 3, allowing memory clocks up to DDR4-4000 without needing the mclk:fclk 1:2 adjustment. This means DDR4-4000 can achieve performance similar to DDR4-3800 in "Matisse." For AMD Ryzen processors, memory overclocking leverages the mclk and fclk alignment, enabling gains up to DDR4-4000 before hitting the 14 MHz ceiling. Beyond that, using the divider can still boost mclk further. I tested DDR4-4000 and found it works smoothly, delivering performance close to DDR4-3800 but with a tighter 14 MHz limit. The system paired with the 4000 model was chosen to tighten timing for optimal results. The monitor is an ASUS 27-inch 1440p display at 165 Hz.