Overclocking is not an exact science nor does it require a degree in rocket surgery. Ryzen processors are more sensitive to memory clock speeds than you may be used to. Fortunately Zen2 is affected far less so than predecessors, making previously obscure clock speeds far less ambitious.
Motherboard choice matters A LOT here - MSI X570 Godlike has been the best performer although we managed decent results with the GA X570 Aorus Master.
Although AMD’s Ryzen 3000 platform supports extremely high memory speeds, the silicon lottery still applies.
Micron will OC the highest and Samsung B-dies are becoming more difficult to find these days so it’s fortunate Hynix also performs well on Zen2 - check your local pricing first.
Sweet Spot (TLDR)
Start with 3600CL16 (1800Mhz) and aim for 1866.5Mhz (3733MT/s).
Anything higher will usually hurt performance.
Actually Start Here
Going into this blindly will end in headache. Trust.
Read these first.
Now What
Prepare for a hell of a lot of testing. No, really.
Stop now and use XMP if you are going to half-ass it, you will thank us in the long run.
Feeling brave?
We recommend performing benchmarks to use as a baseline comparison before tweaking anything.
- Start with the DDR4 OC Guide: https://github.com/integralfx/MemTestHelper/blob/master/DDR4%20OC%20Guide.md
- Download Thaipoon Burner and import your memory profile into DRAM Calc for a safe-ish starting point
- Listen to Yuri @1usmus
Notes
Boards are still rapidly undergoing large BIOS updates, keep an close eye out for SMU and AGESA updates.
We experienced plenty of bugs, instability and regressions on X570. XMP was setting VDIMM to 1.2v. Needless to say, we don’t trust auto settings.
Gigabyte says you shouldn’t load profiles across BIOS versions (in 2019 FFS!) so have fun taking photos of all the settings you change. We recommend grabbing the most recent stable BIOS and praying it works with your hw.
If you are going to be lazy, make sure you manually set:
- VSoC - stay under 1.10 if you can (raising can solve onboard audio glitches)
- VDDG 950mV, VDDP 900mV (wrong voltages can cause system fail to POST)
- VDIMM - 1.45v is safe, 1.5v should be okay for better dies (keep an eye on temps)
- MCLK/UCLK to 3600 (1800Mhz)
- FCLK to 1800Mhz
- Command Rate 1T
Finally:
- In most cases, VSoC > VDDG > VDDP
- Even +25 MHz for the CPU affect the stability of the RAM
- Noise from VRM affects system stability
G.Skill Ryzen Neo (2x16GB)
Here is where we managed to get for safe, stable and obsessively-tested settings.
A decent starting point for Hynix CJR dual rank dies with Zen2.
| VDIMM | VSoC |
|---|---|
| 1.36 | 1.025 |
Primary
| tCL | tRCD | tRP | tRAS | tRC |
|---|---|---|---|---|
| 16 | 19 | 19 | 37 | 56 |
tRAS = tCL + tRCDRD + 2
tRC = tRAS + tRP
Increasing tRCDRD and tRP by 1 can improve stability and reduce memory voltage requirements .
Secondary
Secondary and tertiary timings (except for tRFC) don’t really change much, if at all, across the frequency range.
| tRRDS | tRRDL | tFAW | tWR | tWTRS | tWTRL | tRTP | tRFC |
|---|---|---|---|---|---|---|---|
| 4 | 6 | 16 | 12 | 4 | 12 | 10 | 464-470 |
tCWL: According to the AMD “Let’s Talk DRAM!” post, tCWL should be set to tCL or tCL - 1 and is much more stable at even values.
Geardown Mode forces even tCL, even tCWL and CR 1T
tFAW: Minimum for this timing is 4 * tRRDS (lower actually does nothing)
tWR: Lowest this should be set to is 8, as any lower will cause data corruption.
Tertiary
| tRDRDSCL | tWRWRSCL | |
|---|---|---|
| safe | 4 | 4 |
| tight | 3 | 3 |
Impedence
| ProcODT | ClkDrv | AddCmdDrv | CsOdtDrv | CkeDrv |
|---|---|---|---|---|
| 53 | 24 | 20 | 24 | 24 |
RTT_PARK: RZQ/1 (240)
When RTT_NOM is disabled/off, this value seems to take over.
(Measured in terms of fractions of RZQ, which is a reference 240Ω resistor)Powerdown Mode lowers VDIMM when the system is at idle. Can cause issues with stability and may slightly increase DRAM latency.
Reference
- Extra Hints
- Corsair Guide
- Membench Readme
- Ryzen DRAM calc recommendations
- Hynix presets
- Older Hynix CJR single rank presets
- 3800C14 “exclusive” preset for Zen 2
3900X 4642Mhz / BCLK 102 / 1904 MHz FCLK/UCLK - G.Skill SniperX 3600C19 3600 CL16 (VDIMM 1.39 - 1.42)
- G.Skill SniperX 3600C19 3733 CL16 (VDIMM 1.45 - 1.46)
Quotes
Gigabyte X570 OC Guide:
“For a little extra boost in stability while overclocking we suggest you to try to change VCORE SOC up to 1.20-1.25 volts when using standard air or liquid cooling.”
AMD’s Travis Kirsch:
“So the lowest memory latencies you’re going to get, in the reasonable memory overclock world, is 3,733MHz. When you guys test it, we recommend using the 3,600MHz, with CL 16 or lower – if you can get it lower than that stable it’s great – because that’s going to give you the optimal memory latency. It’s also going to give you a very good price performance module. But with that said, if you’re an enthusiast and you want your high clock speeds, we do allow a path for that”
AMD’s Travis Kirsch again:
“When you look at memory overclocking, MSI Godlike has already demonstrated over 5,000MHz on air. So if you compare that back to first- and second-gen Ryzen, it’s just a huge difference. It’s going to be a lot of fun tweaking the platform and pushing the memory speeds up.”