Overclocking The Core i7-6700K To 4.6GHz On The Maximus VIII Extreme

[Chino]

Before you go jumping into overclocking your CPU, there are two important factors that will determine if your CPU is capable of reaching 4.6GHz. First and foremost, the quality of your CPU will be the main factor in play here. Each CPU is unique and requires a different voltage for a certain frequency. So it is normal that some samples will overclock better than others. And some will achieve 4.6GHz while others can’t. It’s nothing to be sad about. It’s simply the silicon lottery. The second factor to take into consideration is your cooling solution. Heat will be your biggest enemy. Invest in a high end CPU cooler to get the best results as lower temperatures means more headroom to do your overclocking. If you want to push your CPU as far as it can go, then water-cooling is the way to go whether you choose to build your own custom setup or get a closed loop AIO like EKWB’s new EK-XLC Predator 360 used in this guide.


Installing the Intel Core i7-6700K
Place the CPU bottom side up and slide it into the CPU Installation Tool until it clicks into place.



Release the CPU socket tension arm and lift the socket lid. Then carefully place the bracket into the socket.



Lower the socket lid, hook it under screw and secure the tension arm. Then apply thermal paste to your CPU. While there are many techniques for applying thermal paste, the difference in degrees between each technique is so small it’s negligible. The rice sized dot in the middle technique is usually the easiest to perform.



Proceed to install your CPU cooler. If you’re water-cooling your CPU, tighten the mounting screws with your hands in a crisscross pattern until the CPU block is firmly attached to the CPU. Take special care not to overtighten the screws as this may cause irreparable damage to the CPU block while also warping the motherboard. If your liquid cooler uses a custom backplate like the EKWB Predator 360, it is easier to install it outside your case.




Preliminary Test
It is highly recommended to run a quick preliminary test to assess your system’s stability at stock and your CPU cooler’s ability to cool your CPU before embarking on your overclocking journey. You will need the following three programs for this guide.

• ROG Realbench for stability testing
  
• CPU-Z for verifying CPU frequency and Vcore
  
• HWMonitor for temperature monitoring
  

Once you have installed the programs, proceed to open them. Make sure the Benchmark option is selected in ROG Realbench. Normally one run is sufficient to determine your system’s stability at stock. You can choose more runs just to be on the safe side.



After completing the benchmark, you will get a pretty good idea of how well your CPU cooler performs. Remember that you should monitor your CPU’s temperatures at all times. Ideally you would want to keep your CPU’s temperatures below 80C during the entire overclocking process. If your cooling solution is unable to do so or your CPU simply requires too much voltage, you will have to settle for a lower overclock perhaps something in the range of 4.5GHz.

In this particular example, the EKWB Predator 360 manages to keep the stock i7-6700K’s temperatures around 56C in a room with an ambient temperature of 30C.




Tweaking Time
Once inside the BIOS, press F5 to load the optimized defaults then navigate to the Extreme Tweaker tab. Locate the 1-Core Ratio Limit option and input a value of 46 for a 4.6GHz overclock.



Scroll down to the CPU Core/Cache Voltage option and change it from Auto to Manual Mode.



A new CPU Core Voltage Override option will appear. Type in a starting voltage of 1.35.



Press the F10 key and a window will appear showing you a summary of all the options that were modified. If everything is exactly how you had configured it, press OK and your system will reboot.



One of two scenarios can happen.

• If your system fails to boot or load your OS, go back into the BIOS and raise the CPU core voltage using increments of 0.01V.
  
• If you made it inside the OS, proceed to run ROG Realbench’s stress test.
  

Once inside your OS, it’s time to test your overclock’s stability. Open ROG Realbench, select the Stress Test option. Change the duration to 1 hour and select the amount of memory installed in your system using the dropdown boxes. Finally, press the Start button to get the show on the road.

• If your system freezes or crashes during the stress test, return to the BIOS and raise the CPU core voltage using increments of 0.01V.
  
• If your system is able to complete the stress test at 4.6GHz with 1.35V, begin to reduce the CPU core voltage by 0.01V until you find the lowest value to be stable.

There is no official word on a safe CPU core voltage. But it is widely accepted that you shouldn’t exceed 1.45V. If you’re the type of user who likes to play it safe, then keep it under 1.4V. The amount of time to invest in stress testing is subjective. Some users run stress tests for hours and other hardcore enthusiasts for days. If you’re not fond of cooking your CPU during prolonged periods of time, running the stress test for 1 hour should be good enough. In the end, the best stability test is real world usage after all. What’s the point in bragging about passing x amount of hours running y program just to have your system crash doing random stuff?



If all goes well, you should see a results window in ROG Realbench like the one below. This particular i7-6700K sample certainly isn’t one of the best out there. It requires 1.44V to achieve stability at 4.6GHz. Nevertheless, the EKWB Predator 360 performs very well and the temperatures are kept below 80C during the stress test.




Putting On The Final Touches
Once you’re satisfied with your overclock, it’s time to return to the BIOS to make some final adjustments. Navigate to the CPU Core/Cache Voltage option again. Change it from Manual Mode to Adaptive Mode.



This time you will see a few options appear on screen. The only option that will interest you will be Additional Turbo Mode CPU Core Voltage. You will input the voltage that your CPU requires for 4.6GHz. To give your overclock some margin for error, it is good practice to increase your borderline voltage a notch. In other words, if 1.35V is the minimum voltage required for stability, add 0.01V - 0.02V to it. Finally press F10 to save your changes.

[EasyLover]

My CPU has overclocked to 4.7GHz with VCore 1.3. Now, fine tuning of voltage is next step. Real Bench was a success. AIDA64 was a success. Prime 95 was a success. EK Predator 360 kept the temps really well. Max it hit was 53C. Config is: -

Asus MAximus VIII Hero
i7 6700k @ 4.7GHz
G.Skill TridentZ 16 gigs @ 3200MHz [XMP Loaded]
EK Predator 360
Intel 750 series PCIe NVMe 400GB SSD

[BlippyCheese]

@EasyLover - that seems like a great temperature. What are you cooling it with? I have been trying to stay below 70c ... but it has been hard. I am cooling with a EK monoblock on my ME8... and the water temps are generally in the 32C range, so I get a delta of as much as 40C on the CPU.

[EasyLover]

You are not group tuning? I'm using EK Predator 360. What is your ambient temp like? So far I've failed to achieve 4.8 on this chip. 4.7 is going strong.

[BlippyCheese]

I am using group tuning, but in the past I have started with group, then pushed a bit with one and two cores a bit higher. I have so far found this to be harder to accomplish compared to my other M6F (Maximus VI Formula with a i7 4790k ) computer.

Ambient temperature is in the 21C range. I think data that would be interesting across many systems would be ΔT from cooling loop into proc, voltage on proc, T on proc and T on other side of the proc. I have all of these data points for one of my systems and what I observe is typically a 1 to 2C temperature increase across the processor (water) at steady state, no load, and not much different at full load. Processor temp at steady state (no load) tends to be +2 to 3 C over cooling input.

I would experiment with taking off the cooling block and re-applying the thermal compound, but I decided to do rigid tubing this time around ... and that really makes doing things like that loads of work ;).

I have not tried to go above 4.6 yet, but have found it to be completely stable with just the basics - so that is next...

[Nate152]

Great guide as always Chino !

Maximus viii formula - 6700k at 4.8GHz with 1.472v, I didn't run a stress test but it's game stable.

[EasyLover]

1.472 VCore. I'm thinking of trying 4.8 with 1.4 as well. Running 4.7 at 1.3 stable.

[The_F34R_Channe]

Chino, great guide! Two questions; I see you didn't set a LLC level. You left it on auto? I'm tempted to set mine to 5, as it was before. Second question, cache clock; did you leave the min/max on auto? And, how many MHz lower would you set the cache clock than the core clock, provided all options are wide open to begin with? It's my understanding that anything above 4.3GHz can create difficulties. Previously I ran 4.5/4.1GHz (core/cache).

I've learnt that upping the cache clock is good for higher RAM frequencies (not that my 3000MHz would fall in that category), and also that having it far below the core clock (e.g. 4.6 core, auto cache) can cause delays, and so it would be best to have the cache equal to or slightly lower than your core clock.

VID - I've read here it's the requested voltage. Requested, but not provided?

Out of curiosity, have you played with the BCLK, maybe 200MHz with a 23 MP?

Yeah...I think that's more than two questions... 😄

[Nate152]

Great guide as always Chino !

Maximus viii formula - 6700k at 4.8GHz. I didn't run a stress test but it's game stable.

[SinisterDev85]

Very helpful guide Chino. I've had a hellluva time getting my new rig running smoothly, but you and several others here in the forums have really helped me.
Im pretty sure I didn't luck out and get a diamond chip like I did with my 4790k, but Im liking the Hero Alpha and the 6600k is a pretty impressive processor.
I've still got more tweaking to go, but I've managed 4.6ghz @ 1.42v. Which I know is fairly high V, but it just didn't wanna post anywhere near 1.35v. Temps have been great though ! I've seen low of 15C and high of 68C under full load! I still wanna see if I can maintain stability at a little lower voltage.

How do you feel about BCLK over clocking? This is my first DDR4 board and my Titan Z's XMP sets it to 102.10 BCLK. So when my cpu multiplier is at 45, it's actually running at 4.594. I think the ram has given me a harder time getting stable than the cpu.
I've passed Realbench stability tests for 1hr without fail, but I still feel like there's more room for performance improvement. I swear it feel like my Hero 6 /w the 4790k is faster than this pc lol! Especially when it comes to loading programs, which really strikes me as odd because Im using one of the fastest new NVME SSD's in this Hero Alpha build.

[Chino]

Tweaking the BCLK might help you squeeze a few extra megahertz from your overclock.