Same RAM units fail to operate together at identical performance levels.
Same RAM units fail to operate together at identical performance levels.
I refreshed my PC about two years ago using the same components (2x16GB DDR4-3600, G.Skill Trident Z Neo, Model F4-3600C16-16GTZNC). Everything worked fine then. Recently, I upgraded the RAM to the same identical set (same model numbers). However, the speeds vary significantly, and I’m unsure how to resolve it. I’m not comfortable with overclocking or BIOS tweaks. I’m wondering if all the speeds should be 3600 MHz. CPU-Z indicates slots 1 & 2 run at 2666 MHz, while slots 3 & 4 are at 2132 MHz. The BIOS lists DIMM A1 & B1 at 2666 MHz, and A2 & B2 at 2133 MHz. I’ve attached screenshots from CPU-Z and my BIOS. My current specs are listed below. CPU: AMD Ryzen 9 3900X 12-core MOBO: ASUS TUF GAMING X570-PLUS (WI-FI); RAM: G.SKILL TRIDENT Z NEO 4x16GB DDR4-3600; GPU: NVIDIA GeForce GTX 1080Ti; PSU: Corsair RM850. Thanks for the help.
Check the CPU-Z display for DIMM details, not SPD. RAM should be operating around 1800Mhz if everything is functioning properly.
Different parts can have the same part number but vary in their actual memory ICs. For example, the 3600 CL16 supports multiple ICs, and checking CPU-Z reveals that some DIMMs are single rank while others are dual. This means performance can be similar, but compatibility issues are more likely. There’s also confusion in the BIOS screenshot showing mixed JEDEC speeds, suggesting the second half might just display stick specifications. To get accurate details, use CPU-Z to view the memory settings or try ZenTimings for more precise data.
Running at 3600MT/s effectively means around 3600MHz, which is why it appears on the box or in the BIOS. If the BIOS displays the same speeds as the SPD readout, it probably matches what the SPD panel shows—reading the standard specifications from each DIMM rather than the actual performance it delivers.
That matches what I mentioned—it's operating at 3600MT/s. The DRAM speed is half the actual frequency since RAM operates at double data rate, which means the BIOS is simply displaying the JEDEC specifications for those modules. No concerns here; your RAM is functioning within its rated parameters.