How To Overclock AMD Ryzen CPUs

BIOS Options

Overclocking Options

Overclocking through Windows is convenient, but we still prefer locking in new settings through the BIOS. This is doubly important, we think, when it comes to a brand new platform like AMD's Ryzen.

What follows are the most notable settings from our Asus board's BIOS:

  • Ai Overclock Tuner: Set this to manual for access to reference clock adjustments, or set it to D.O.C.P. to pick a memory overclocking profile (related parameters are adjusted automatically).
  • BCLK Frequency: We'll come back to this very important setting later in the article. It can be adjusted from 85 to 145 MHz, according to the settings. By default it should be near 100 MHz, but we have recommendations of our own.
  • CPU Core Ratio: This is a multiplier used to determine the processor frequency. Raise it to overclock your CPU. Be careful, though. When the ratio is not set to Auto, AMD's XFR technology is deactivated. The processor switches automatically to overclocking mode and all power-saving features are deactivated. It is adjustable in increments of 0.25x.
  • Memory Frequency: System memory frequency, from 1333 to 3200 MT/s. You can go even further using the BCLK Frequency field. This is a very important parameter for optimizing performance, and we'll go into more depth on it shortly.
  • SMT Mode: Simultaneous Multi-Threading is similar to Intel's Hyper-Threading. Be careful; we had trouble with our motherboard when this option was set to Activated. Leave it on Auto; SMT will still be activated and you won't run into the bugs we did.
  • CPU Core Voltage Override: This allows you to regulate your processor's core voltage. Asus advises against exceeding 1.4V. AMD recommends a 1.35V maximum voltage for long-term overclocks, and although the company says Ryzen can withstand 1.45V, longevity may be affected.
  • DRAM Voltage: Raising the RAM voltage can help stabilize an overclock. A value of 1.35V is generally sufficient. For lofty overclocks coupled with aggressive timings, this can be raised up to 1.8V without additional cooling if you're using Samsung B-die chips.
  • PLL Voltage: We recommend manually locking this to 1.8V. If you leave it set to Automatic, there's a risk that your motherboard will raise it, resulting in a temperature increase. It's a useful knob to have when overclocking under liquid nitrogen (notably for the RAM).

If you click on the External Digi+ Power Control sub-menu, you get these options:

  • Load-line Calibration: According to our testing, Level 1 yields the best results.
  • CPU Current Capability: To avoid overclocking limitations, we recommend raising this to 140%.

As a reminder, LLC helps stabilize the core voltage under taxing CPU loads. When the processor is at rest (idle), it consumes little energy; therefore, the 1.35V it needs is easily supplied. Once the workload intensifies, though, voltage drops a bit (to 1.3V, for example). Obviously this is not good for stability. Motherboards equipped with load-line calibration functionality can increase core voltage under load to offset this effect.

LLC Testing

We tried a number of the modes offered by Asus' Crosshair VI Hero, and recorded their results using our voltmeter.

With the CPU set to 1.35V, all of these profiles fed our sample close to 1.357V at idle. Under load, however, they can increase significantly. 

LLC 1 (Auto)1.357V1.36V
LLC 21.357V1.37V
LLC 31.357V1.4V
LLC 41.357V1.42V
LLC 51.357V1.44V

It looks like the LLC setting is a little aggressive, given the voltage overshoot at idle. At Level 1, the increase under load is reasonable and won't cause any problems. Our testing showed the Auto mode's results to be similar, but lock in Level 1 just to be sure.

The last level is fairly crazy, pushing 1.44V instead of 1.35V.

Be careful with CPU voltage. Setting 1.35V in the BIOS does not mean the processor receives this voltage, proven here with LLC 5, which adds nearly a tenth of a volt. For the remainder of today's story, the values we're reporting are verified with help from Asus' test points.

Maximum Voltages Recommend by Asus

Ambient Recommended
Ambient Maximum
LN2 Recommended
LN2 Maximum
CPU Core Voltage
Up to 1.45V
Up to 1.95V
SOC Voltage
Up to 1.30V1.20VUp to 1.40V
DRAM Voltage1
1.40VUp to 1.90V1.80VUp to 1.90V
1.8V PLL Voltage
1.80VUp to 2.10V3.00VUp to 3.20V
1.05V SB Voltage
1.05VUp to 1.40V1.30VUp to 1.40V
1.8V Standby Voltage1.80VUp to 2.10V2.10VUp to 2.30V
2.5V SB Voltage
2.50VUp to 2.80V2.70VUp to 2.80V
1 Depends on the DRAM sticks; the limit is considered from CPU IMC side.

DRAM Timings

The DRAM Timing Control sub-menu grants access to memory timings. No, you aren't seeing things; there are currently only five options. The right memory settings are very important on this platform, so we'll dedicate an entire page to optimizing them properly.

Not all of the other parameters available in the DRAM Timing Control After Training menu are applied. At least, that's the case in firmware version 5803, which we used. Perhaps AMD will allow motherboard manufacturers to unlock these settings in future BIOS releases.

A BIOS Cheat?

To improve performance in Windows, AMD recommends using the High performance power plan. What impact does this have? In order to answer that question, we tried it out.

Also, we turned on the BIOS-based “Performance Bias” option and ran Geekbench 4. This option purportedly allows overclockers to score more points in competitions. Our Geekbench scores are the average of three consecutive runs.

Geekbench 4

Mem. Copy
Mem. Latency
Mem. Bandwidth
Mode: Normal
Bias: Auto
Mode: Performance
Bias: Auto
Mode: Performance
Bias: Geekbench 4

Setting the power plan to High performance does yield a speed-up (a small one in our case). But it's going to have more of an impact on a CPU that hasn't been overclocked, and can drop its frequency lower at idle.

The “Performance Bias” option found in the BIOS adds even more performance to Geekbench, even set to the default Auto mode. By changing it from Auto to Aida/Geekbench, we record gains in each of the five values tested. Certain motherboard reviewers may see this as cheating, but it'll be a blessing during overclocking competitions.


MORE: Intel & AMD Processor Hierarchy

MORE: CPU Overclocking Guide: How (and Why) to Tweak Your Processor

This thread is closed for comments
    Your comment
  • drinkingcola86
    Page 4 third paragraph.

    "Also, we observed that this this offset of 20°C is a loose approximation,"

    Needs correcting. One "this."
  • ykki
    Power consumption benchmarks?
  • jkhoward
    Dang-it guys. The 1080 doesn't freaking work well with the new AMD CPU. You know this. Why would you not choose an AMD card? Trying to make AMD look bad again?

    <edited for language>
  • popatim
    What evidence do you have for that statement jkhoward?
  • MeanMachine41
    612443 said:
    Dang-it guys. The 1080 doesn't freaking work well with the new AMD CPU. You know this. Why would you not choose an AMD card? Trying to make AMD look bad again? <edited for language>

    I have evidence to the contrary and the GTX-1080 works well with new Ryzen 7 1800X.

  • Kenneth_72
    AMD's is missing it's opportunities. They better start hitting the ground running if they want to compete AND WE NEED THEM TO COMPETE!
  • CountMike
    Problems are more of BIOS oriented, AGESA being main culprit.
  • Akindabigdeal
    My 1080 works great with my 1700x
  • mike3456
    I look forward to more articles like this as Ryzen matures. Great job!
  • JamesSneed
    For anyone looking to OC Ryzen this video from an AMD engineer is pretty interesting.
  • It is horrible overclocker. I have 6900k running 4.4@1.25V and on Load temperature doesn't go over 52C, idles ~24-30C.
  • gdmaclew
    I noticed the BIOS screen shots were dated March 7th. Which version of the BIOS was used?
  • JamesSneed
    2164959 said:
    It is horrible overclocker. I have 6900k running 4.4@1.25V and on Load temperature doesn't go over 52C, idles ~24-30C.

    Ryzen doesn't OC great but that 6900k is a $1000 CPU. From a value perspective a 1700 OC'ed to 3.9-4.0Ghz is only a few percent behind the 6900k and we are talking 3x less cost vs the 6900k so there is that.
  • elbert
    That was a great review Wizerty. Will we see the same tests for the 6 core and quad's? I would guess the 8 core has the best possible settings but there is always the chance they dont.
  • techy1966
    Very nice write up it sounds like you had a lot of fun doing all of this. It is always great to learn something new and what better way than to do that on a completely new platform. Where you kind of have to go back to the basics and find what the limits are and what the settings you apply to the system effect overall performance.

    I have bookmarked this write up because I plan to get a Ryzen based system down the road and most likely will be the R7 1700 it makes the most sense. I hope that if there is a big batch of bug updates or added features to the bios that you will do a follow up of this to show the gains if any. Thank You
  • rwinches
    Just make sure you don't overclock your i7 7700K as per Intels instructions

  • JamesSneed
    ^ Seriously, wtf is Intel thinking.
  • BulkZerker
    310904 said:
    What evidence do you have for that statement jkhoward?

    for one. . . there's some stuff on the L T T forums as well. It's over a month old, dunno if the issue has been addressed by nVidia or not. They certainly have not acknowledged it publicly. Otherwise you'd probably have heard of it.

    But not on Tom's, they'd never slander big green.
  • Plumboby
    intel is dead in the water once amd fixes the bugs in the new set ups. Mixed results so far atm but things are getting better seen the video hand having amd being so open when intel arnt w8 till the end of the year for the 2nd gen rysens processors & motherboards always the 1st gen or anything is buggy usually technology wise i be upgrading soon from intel usually an intel fan but over the way intel have been stacking their prices & push on the skylake series boards kaby lake shows no intrest to me i rather pay the diffrence & w8 for amd to sort the rest the issues then i be going amd & do some testing. Come on AMD give intel the scare they need as the next lot of video cards are going be worth the wait
  • __Isomorph__
    wizerty, what are those other boards you mentioned in passing that have an external clock and allow increase of ref clk above 100Mhz? does the Taichi x370 allow this?
  • JamesSneed
    2449301 said:
    wizerty, what are those other boards you mentioned in passing that have an external clock and allow increase of ref clk above 100Mhz? does the Taichi x370 allow this?

    The are the ones I know of that have an external clock generator.

    Asus Crosshair 6 Hero, Asrock Taichi, Gigabyte Aorus Gaming K7
  • Logic-Elliven
    NB: G.Skill's Flare line are just rebadged Ripjaws with $ 30 tacked onto the price.

    I note that there was no mention of bus termination impedance/resistance setting tweaking in the writeup..?!?

    There is a piece of software called 'Project Mercury' that avoids inter CCX thread hopping and SMT until more threads than cores per CCX and allows the switching off of SMT without a reboot.
    CPU utilization: ~0% ie: Bloody good software!
    The site and name need work and some anti virus packages take offence to the compression used in the software>
    Virustotal shows 'UDS:DangerousObject.Multi.Generic' for 3 out of 60 AV scans = false positive to me.

    Project Mercury:

    If it had been used for this review it would have saved tonnes of time in reboots...
  • __Isomorph__
    @Logic-Elliven: thanks, awesome resource. hope it doesn't rootkit my PC.
  • 0ldsch00l
    Hell nof if virustotal flags it I dont care if you think its a false positive, I wont install that.