Intel Kaby Lake i7-7700K CPU Overclocking Follow-up

Last week we shared our overclocking results with our retail purchased Core i7-7700K Kaby Lake processor. We then took the Integrated Heat Spreader off, replaced the Thermal Interface Material and tried again for 5GHz with 3600MHz memory and failed. This time, less RAM MHz and more core voltage!

7700K Overclocking Results

This is a follow-up article to what we shared with you last week; Intel Kaby Lake i7-7700K CPU De-Lid & Re-Lid Results and a follow-up as well to this news post; Retail 7700K Not Up to 5GHz - 3600MHz. What we found was that no matter how hard we tried, we could not get our retail purchased 7700K up to par with one of our sample 7700K CPUs that would easily clock to 5GHz with a 3600MHz memory clock at 1.32v vCore.

What we have found in our experiences with the Core i7-7700K when it comes to overclocking, is to not necessarily expect an "easy" 5GHz overclock. However there are certainly some caveats to this observation and I wanted to discuss that here.

After our delidding article last week, we kept on and kept on testing after we saw a reduction in package temps by over 20 degrees C. We had high hopes.

We did find out the following:

1. If we turned off HyperThreading on the 7700K, we could clock the processor to 5GHz/3600MHz. This took an amazing heat load off the CPU. This however basically turns your 7700K into a 7600K. Given that a 7700K costs $350, and a 7600K costs $235, this may not be the most economical or efficient route to a 5GHz build.

2. Pulling back greatly on our RAM speed did allow us to reach our 5GHz on the 7700K with HyperThreading turned on. However, we had to pull back RAM speed a lot. I tested 3333MHz, 3000MHz, 2800MHz, and 2666MHz. Only once we got down to 2666MHz did we see full load (32GB in this case) become stable for 8 hours.

So surely there are some caveats to reaching 5GHz on this CPU, and if you are focused on getting to the 5GHz pinnacle there are some things you can do. Turning off HyperThreading does not truly seem reasonable to me considering the cost associated with chunking HyperThreading out the window. When it comes to RAM speed, I would suggest that 2666MHz is the "bottom" of where most enthusiasts will want to run their system memory at. Of course this is a personal preference.

Beyond 5GHz on the 7700K

One thing that will get you very optimistic about 7700K overclocking is that I could easily boot into Windows 10 64-bit at 5.3GHz with a 2666MHz memory bus, albeit with a very healthy vCore, which we will go into more below.

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However optimistic, let's not get our expectations out of line here! Any kind of load at all on the system would immediately give us a BSOD. We tried a good bit at 5.2GHz as well, but that was not realistic either.

What we did find was that with our delidded and liquid metal retimmed 7700K, we could accomplish a stable 5.1GHz/2666MHz overclock that remained stable under RealBench v2.44 for a full 8 hours.

The screenshot shown here does show me using a 4GB RAM load instead of the 32GB load available to us with our footprint. I did follow-up our testing last weekend with two more sessions of 32GB testing for a full 16 hours of stability.

One thing that we very much need to discuss here is the vCore needed to get this 7700K CPU stable at 5.1GHz. It scaled up to a whopping 1.5v. We set 1.47v in the UEFI. We are using a G270X-Gaming 9 motherboard for this testing. As we have found with testing on other GIGABYTE motherboards, we did need to change the CPU LoadLine Calibration to "Turbo" on the Gaming 7 and "Extreme" on the Gaming 9. This scales the vCore under load to what was needed levels for this particular CPU. The actual vCore was identified by CPUz to be fluctuating between 1.488v to 1.500v. With this delidding and retimmed 7700K we saw our maximum per core temperature reach 91C with the other three cores in the high 80 degree C range.

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The Bottom Line

While your brand new Core i7-7700K may not be up to the pinnacle of 5GHz core clock and 3600MHz RAM clock like we have seen on our "golden" CPU, there are certainly some things you can do in order to get there. First and foremost is to back off RAM clock. After that, turning off HyperThreading can greatly reduce the load on the CPU cores as well and possibly give you some more headroom, but what is the point of the 7700K if you are going to do that? Third and foremost is that you can certainly pour the vCore voltage to it. Obviously that comes with risks in terms of heat and long-term stability. While I would not suggest you run your 7700K, or any Kaby Lake processor at such high vCore for long periods of time, it might just get you where you want to go in terms of Kaby Lake overclocking.

I did talk to ASUS this week about Kaby Lake overclocking. I reached out to them and asked if they had run across any tweaking "secrets" in the last couple of weeks since we had last talked. This was the reply:

No tricks for CPU core freq - it’s all cooling and Vcore.

So, while we have some of the most advanced motherboards we have ever seen in the last 20 years, it seems that we are back to where we started with CPUs and overclocking, not that that is a bad thing.

We have our retail purchased Intel Core i5-7600K on the test bench now and it is humming along at 5GHz/3600MHz at a 1.35v vCore.

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Once we figure out everything we want to know about this 7600K, we will delid it as well. This time I promise not to lose the video.