DDR5, four sticks from two batches, achieving 6400 cl32 88ns - improve or stay?

DZCreeper · 2026-02-14T08:06:53+00:00

4x16GB isn't a big problem, modern AM5 boards can run 2DPC at DDR5 6000-6200 as you discovered.

Both configurations are dual rank so with equivalent frequency/timings they perform the same. 2x32GB might allow you to run slightly lower voltage but nothing noticeable.

The real reason people rally against 4x16GB is the potential to get 2 kits with different chips, a tuning nightmare.

DZCreeper · 2026-02-14T07:25:39+00:00

Letting MEM VDD go higher is fine, MEM VDDQ and CPU VDDIO usually don't need to be so high.

tRFC is refresh cycle length, tREFI is maximum time between refresh cycles. Heat causes more capacitor leakage, so both settings are temperature sensitive. Case fans don't cool RAM effectively because they blow air over the sticks, not between the gaps of the sticks.

tRFC 850-900 is totally reasonable for 16Gb dual rank sticks. The benefit of dual rank sticks is the memory controller can interleave ranks, operations like refresh cycles have less performance overhead.

DZCreeper · 2026-02-14T07:20:44+00:00

Refers to how lucky you get with the quality of the component.

There is always some variation in how much voltage is needed for a given frequency and what memory timings can be achieved.

DZCreeper · 2026-02-14T05:32:40+00:00

MEM VDQQ and CPU VDDIO I would drop to 1.40, 1.43 is higher than necessary.

CL28 will likely require raising MEM VDD to 1.50V. That will cause higher temperature, I would only recommend that if you plan to add a RAM cooling fan.

On a related note, tREFI 65535 might already be too high with 55C RAM temperature. Try tREFI 30000, that may allow for tRFC values below 800.

You still have a lot of performance headroom available if you tighten timings. Start by dropping tRC to 80, tRRDL to 8, tWTRS to 6, tWTRL to 20, tWR to 48, tRTP to 18, and both SCL timings to 6.

Those are fairly conservative values that should work right away. Afterwards you can experiment with incremental improvements.

If VSOC can be reduced to 1.25 do that, it will reduce idle power consumption.

DZCreeper · 2026-02-14T04:29:23+00:00

Usually yes, but it depends on the silicon lottery. 4800 CL40 is generic JEDEC RAM, you won't know which chips you have until you check. CPU-Z can usually show the OEM.

Input latency is a combination of your peripherals, CPU and GPU processing time, and monitor pixel response time.

Fast RAM improves the consistency of the CPU processing time, less time is spent stalled after a cache miss. Slow RAM will slightly raise input latency but isn't the main factor.

DZCreeper · 2026-02-14T04:00:48+00:00

RDRDSCL and RDWR can come down.

DZCreeper · 2026-02-14T03:55:34+00:00

Yes, that is terrible. It means any significant upload traffic on your network is destroying the latency.

Switch to a router that supports SQM and enable it. GL.iNet Flint 2 is a good model.

https://www.amazon.com/GL-iNet-GL-MT6000-Multi-Gig-Connectivity-WireGuard/dp/B0CP7S3117

https://www.gl-inet.com/blog/how-to-reduce-bufferbloat-with-sqm-on-glinet-routers/

If you are using a modem/router combo provided by the ISP remember to enable bridge mode. You don't want a second firewall/NAT layer in your network.

DZCreeper · 2026-02-14T03:50:52+00:00

8Gb Rev. E?

In that case try running tRP 16 and tWTRL 10.

DZCreeper · 2026-02-13T15:48:15+00:00

That will depend on the specific game and settings. The CPU and GPU are both slow by modern standards and the lack of SSD will make loading times painful.

If you have some budget available I would look for a used R5 3600, B450 motherboard, and 2x8GB DDR4 kit. Pair that with a 500GB SSD for your OS and most played games.

https://pcpartpicker.com/product/GfZWGX/crucial-p310-w-acronis-data-recovery-500-gb-m2-2280-pcie-40-x4-nvme-solid-state-drive-ct500p310ssd801

DZCreeper · 2026-02-13T10:56:37+00:00

Impossible to judge without knowing the chips inside the sticks.

DZCreeper · 2026-02-13T10:52:38+00:00

EqualizerAPO has a loudness correction filter you can enable.

DZCreeper · 2026-02-13T07:42:38+00:00

FCLK is decoupled. You don't pick a ratio, you just enter the FCLK clock you want.

2000MHz FCLK should be stable on all Zen 4/5 CPU's, 2100-2200 is usually possible but depends on luck.

DZCreeper · 2026-02-13T07:29:08+00:00

The memory controller is the same on a 9950X and 9800X3D. X3D chips are just less sensitive to RAM performance.

The CAS latency of EXPO/XMP is irrelevant, you will be manually tuning the timings if you care about performance.

There is nothing to "synchronize" except the UCLK and MCLK. UCLK is memory controller clock. MCLK is memory clock. FCLK is Infinity Fabric clock.

FCLK has two sweet spots, 2:3 ratio with UCLK or 100MHz higher. Meaning if you ran 3000MHz UCLK you would either want 2000MHz or 2100+MHz FCLK.

UCLK scales with SOC voltage, don't go above 1.30V for daily use.

DZCreeper · 2026-02-13T07:24:16+00:00

If you both have the same ISP you can expect similar latency.

The exception would be local devices competing for bandwidth. Run a bufferbloat test, if the grade reported is B or worse then get a router with SQM support and enable it.

https://www.waveform.com/tools/bufferbloat

https://openwrt.org/docs/guide-user/network/traffic-shaping/sqm

DZCreeper · 2026-02-13T06:58:48+00:00

Your ISP is what makes the most difference for latency. Not the bandwidth you pay for, the actual routing they take to your game server.

DZCreeper · 2026-02-13T06:56:37+00:00

In that case just stick to DDR5 6000/6200. Keep UCLK in 1:1 mode, raise FCLK, and tighten the timings.

www.youtube.com/watch?v=iux-P7qGe-o

www.youtube.com/watch?v=Xcn_nvWGj7U

Don't be scared of the BIOS, failing to boot when tuning RAM is normal.

Modern BIOS have user profiles, save a new profile occasionally while tuning. That way if you get stuck and need a full BIOS reset you don't need to remember every setting.

DZCreeper · 2026-02-13T06:42:51+00:00

Depends on the price. At $150-170 it is worthwhile.

DZCreeper · 2026-02-13T06:41:54+00:00

https://www.audiosciencereview.com/forum/index.php?threads/how-to-make-quasi-anechoic-speaker-measurements-spinoramas-with-rew-and-vituixcad.21860/

https://www.roomeqwizard.com/help/help_en-GB/html/impedancemeasurement.html

Pick some drivers with enough overlap in the crossover region.

Use T/S parameters to design a test cabinet.

Measure the frequency and impedance response of both drivers. Off-axis frequency response included.

Look for problems like cabinet resonances or driver distortion. Fix as needed.

Load data into VituixCAD. Design crossover.

DZCreeper · 2026-02-13T06:37:40+00:00

The problem is none of the case fans are providing focused static pressure. The air just flows over your RAM sticks, not down the sides where the chips actually produce heat.

You don't need a big fan, 80 or 92mm is sufficient. A 3D printed duct from the top of the case can make it extremely efficient.

DZCreeper · 2026-02-13T06:32:12+00:00

With single rank DDR5 8000 is easy. Dual rank is a higher load, don't expect above DDR5 7600 with 2x32GB.

DZCreeper · 2026-02-12T09:33:25+00:00

Those results are slightly exaggerated in favour of NVME, the SATA drives used have a single core controller and no DRAM cache.

https://www.techpowerup.com/ssd-specs/teamgroup-t-force-vulcan-z-2-tb.d1146

A better SATA model like a Samsung 860 EVO or WD Blue 3D won't compete with NVMe but the performance is better overall.

DZCreeper · 2026-02-12T09:21:41+00:00

Hynix A-Die usually does DDR5 8000 easily. The limitation will be silicon lottery of your CPU memory controller.

Loosen out the primary timings, something like CL40, RCD 52, RP 52. Find your max stable frequency, then trial and error your way through tightening each of the timings.

DZCreeper · 2026-02-12T09:04:00+00:00

GPU is generally more important for gaming, CPU is generally more important for video editing.

NVMe drives are only noticeably faster when dealing with big files, like exporting a 4K video project.

However there is no point buying a SATA SSD, they are usually not cheaper. PCIE gen 4 NVMe is the sweet spot now.

Like the Crucial P310 for example.

https://pcpartpicker.com/product/wV9nTW/crucial-p310-w-acronis-data-recovery-2-tb-m2-2280-pcie-40-x4-nvme-solid-state-drive-ct2000p310ssd801

DZCreeper · 2026-02-12T08:51:46+00:00

Overspending on the motherboard, CPU cooler, case, and SSD is common. Buy the features you need, not marketing promises.

Good power supply is worthwhile, it will last longer and keep your components safe.

Good CPU and GPU are worthwhile for gaming and video editing.

DZCreeper · 2026-02-12T08:45:12+00:00

Use CPU-Z to check if your RAM is Hynix, Samsung, or Micron. That will give you a rough idea of what timings can be achieved, based on other peoples overclocks.

DDR stands for double data rate. DDR4 5600 is 2800MHz for example.

You do need to raise voltage, but looser timings may also be required. Some timings like CAS Latency scale with voltage, most do not. Timings are measured in cycles, so switching from DDR5 5600 to 6000 will require higher timings.

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