Important sequence for CL, TRCD, TRP and TRAS
Important sequence for CL, TRCD, TRP and TRAS
For a few weeks now, I've been pushing my RAM to higher speeds. I've reached a point where I need to rethink my strategy. It seems I'm still unsure about the right sequence for overclocking memory timings. Do you remember the standard order: CL, tRP, tRAS, tRCD? Is that correct? Also, comparing DDR4 15-18-19-32 at 3600MHz versus 17-20-20-38 at 3800MHz – which one performs better? I'm still working on the latter and have found the lowest stable clock at CL 17. Should I focus on lowering tRP first or tRCD next? On one side, some sources suggest CL/ram speed is key, so a lower 15kHz might be preferable over a higher 1900kHz. But I haven't fully adjusted the timings yet and see better results with the 3800 series stable settings. Regarding voltage, I've set it to 1.36V, which is above the MSI B450's maximum – likely a real setting. I'm keeping timings higher to ensure stability now. My testing notes: I remained stable in memtest86 for several nights (over 7-8 hours), running multiple tests back-to-back while tweaking the 3600 profile. I once tried changing timings one at a time, which caused instability and made me question whether the XMP setting was correct. After several BIOS updates and more memtest86 runs, I finally tested the RAM in XMP mode, and it passed. Still, I suspect a small issue might be lingering. My experience shows that memory can behave unpredictably, especially when secondary timings are adjusted. I've also noticed that voltage settings seem to work better than I thought, possibly because the motherboard automatically sets some defaults. Despite these uncertainties, I'm committed to seeing through this. If it doesn't hold up in real-world use, I'll try again – but right now, I'm focused on getting stable timings.
The question focuses on small variations. The example timings seem poor, and it asks about the memory type—AMD or Intel. It also mentions needing clarification on the system.
I see a slight variation from the xmp stock profile to my 3600 OC or 3800 WIP configuration. I'm trying to determine which one performs better based on the shortest timings, since I enjoy testing and it's not feasible to physically adjust hardware. TL;DR: The main focus is on RAM order for CL, TRCD, TRP, and TRAS.
Long question: When aiming to reduce primary RAM timings, what should be prioritized in sequence? Which one should you address first? By which rule does a single timing most affect latency reduction? Confused because some depend on others. So far I think the key order is CL, then tRP, tRAS, tRCD.
Logic behind: I plan to tighten timings, so starting with the highest impact makes sense—like 15-18-19-32 3600 (my tRCD split at 17T and 18T) versus 16-19-19-39 3600 or 17-20-20-38 3800. This is CL, which can't go lower, so I’ll focus on the rest.
I’ve tested an AMD Ryzen 5 3600 at 4.3GHz all cores, 1.25V, and noticed a small difference—likely in benchmarks only. Once that’s settled, further tweaks will be minimal, probably around imperceptible changes. Edited May 6, 2020 by nutzaalex
CL first, the rest follows. Target is 3600mt/s with several sub timings. 16-16-16-16-26-46 1T and 3800mt/s at 18-18-18-18-28-52 1T. Aim for 1.45v or less. Trfc influences performance significantly. It's one of many sub timings, but most impactful. Since you're not doing competitive benchmarking, stability is key. If SOC voltage drops, consider raising it for better stability. Disable gear down mode if you notice odd CL latency. Overclocking may require turning off power down mode as well. Try to smooth your timings as much as possible. An example would be 16-18-18-18.
I increased it to 1.12... I set it at 1.2 as the limit, but don't want to go higher than that. Disabled everything except what appears correct—like 16/1800 is quicker than 18/1900, so 3800 doesn’t seem worth trying. How did you arrive at these numbers? It’s interesting because I thought clearly about this; knowing CL is most important explains why it should be 15 instead of 16 if we can drop one point.
Well 15 corresponds to a 2133 Jedec timing setting. As you observed, this is the sole instance where "gear down mode" disables itself. AMD’s memory controller generally prefers consistent latency patterns, and odd cas latencies are uncommon—most XMP profiles use even numbers, likely mirroring Intel’s approach. If you’re aiming for precision, targeting two clocks would be ideal. A CL 15 won’t outperform a well-tuned CL 14 at 3600mt/s with the right memory. My 2700x can handle it, but a high-performance die kit and higher voltage would push your limits. For daily use, 3600mt/s at CL 16-16-16 seems like a solid choice. If you’re chasing top results, I have some options too. Just keep in mind, you’ll need to adjust the voltage for better gains. You’ll likely need some scaling involved.
Read numerous remarks and inquiries as I typed. Everything is fine. Consider pacing like traffic rules—adjust speed as needed. Just establish a steady pace for optimal results.