Memory capacity reduced from CL16 to CL15, yet remains at CL16.
Memory capacity reduced from CL16 to CL15, yet remains at CL16.
Since I don't think there is much point in overclocking 3600MHz RAM anywhere for Ryzen 5800X I've decided to lower the timings instead. And I went from 16-19-19-19-39-85 2T down to 15-18-18-18-35-58 using same voltage of 1.35. However, for some incredibly bizarre reason, the primary timing, CL doesn't want to go down. When I fire up CPU-Z and check the timings, it still says it's CL16. But in BIOS, it says CL15. What the hell? In 20+ years of doing this I've never encountered anything like this. Is this like a common thing that I'm somehow not aware or something? I'm pretty sure it wouldn't even post with CL14, but why it refuses to accept CL15 ?
It seems the settings are being adjusted automatically in AUTO mode, likely by default. The changes appear to affect only certain timings without affecting others. When using CL14, the system didn’t start properly, which matches expectations. With CL15 it boots successfully but displays a different CL16 status. Since you haven’t experienced this behavior with X99, you decided to keep it unchanged. This setting probably relates to power management or performance tuning, possibly adjusting timings based on usage patterns rather than a clear explanation in the BIOS.
Attempted to turn it off and the system still can't start even with CL16. From what I understand about this feature, it alters DDR memory behavior on a clock cycle level (high/low edges). This makes me think that pushing timings or MHz too hard isn't very effective if it's interfering with DDR clock cycles just to force operation, even though it might otherwise fail without this Geardown mechanism. It feels similar to the issues seen with ECC memory on graphics cards—you can push them to extreme speeds and they still perform poorly. Right now I'm testing at 16-17-17-17, but based on what I've read, it's likely underperforming compared to the stock speeds of 16-19-19-19.
Increase memory voltage for optimal efficiency. Focus on speed without needing identical timing to others. Higher bandwidth often boosts performance more than lower latency. (Target frequency around 3733mhz). Pursuing a 1ms latency improvement may be counterproductive if you're overclocking incorrectly.
I've reviewed the RAM scaling settings and for the 5800X model, 3600-3733 MHz appears to be the optimal range where performance improvements are most significant. Values outside this window often result in reduced scores and frame rates in games. I plan to target that range. Currently, I'm applying an XMP profile at 3600MHz and manually adjusting it to 1T, which typically enhances performance without needing higher voltages. Testing 3733MHz with identical voltage and timings worked well, though further validation is needed for stability. In both cases, the fabric speed reached 1800 MHz or 1866 MHz, achieving the desired 2:1 ratio. According to CPU-Z benchmarks, this configuration yielded the best results—653 for single-threaded performance and around 66,000 for multicore. Attempting lower timings caused scores to drop by as much as 50 for a single core, which was a substantial loss. I'm considering using GearDown to disable it while keeping the system booted.