Deep Dive Into Kaby Lake Refresh Mobile Processors

October 23 2017 · 4 minute read · by NavJack27

I wanted to take a deep dive into the Kaby Lake-R processors but to do that you need to educate yourself on the past. Before this generation to get a true four cores and eight threads you needed to purchase a computer with an i7. Higher core count plus frequency also meant more TDP. To more easily visualize this, I created a chart for you to reference.

For this historical data I used Wikipedia and CPU-World along with the Intel ARK. Sadly I don’t have any of the previous generation four core eight thread mobile CPUs on hand to get first hand test results with Passmark PerformanceTest. The low test result with the 8650u was due to the sample size only being one.

Time to get down to the fun stuff that I’ve discovered about the Kaby Lake-R. Out of the box HP has configured this CPU to the Intel spec for the most part. In windows they have their own power profile but curiously it seems that the Intel SpeedShift technology isn’t enabled. Now I might be wrong with this, I was only able to detect this setting with the program ThrottleStop and I’m not sure if the default settings of that program override the default settings in the OS when you first launch it. Later on, I learned that I could use the RightMark PPM Panel program to dive even deeper into the Windows power settings. Another program I installed was the Intel Extreme Tuning Utility which allowed me to tune and verify turbo settings and voltages. After a bunch of screwing around and figuring things out I was able to undervolt the CPU with an offset of -0.075v and get the all core turbo to stick around at 3ghz give or take at 21w package and 20w core while keeping the 3.4ghz short turbo on all cores along with the ability to go down to 0-1w idle at 800mhz. The temperatures did go up with these settings under a longer-term load on the CPU from about 65c at stock to 85c with the overclock and undervolt but without the undervoltage it would overtemp and throttle. The temp throttle point is 100c which seems very generous, but I’d assume its standard for a laptop. The custom settings that I’ve arrived at do seem to positively affect battery life and performance. The only con would be that it’s kind of a trick that you need to play on the system to get these settings to take effect.

Honestly, it’s better late than never that we see an i5 with eight threads. I won’t go as far as to say that it’s amazing and innovative. I will say that Intel has executed it correctly. Not only is the desktop 8xxx line of CPUs totally different but the mobile chips seem to really show what Intel can do with their process-architecture-optimization-optimization. We can speculate on if Intel is reacting to competition or are just trying to maximize profits by using the most of their die yields. While there might not be any IPC improvement they have worked on power management and well, just power delivery and efficiency in general. If you are a person who overclocks that’s great but it’s also great for the laptop space too. If you can hit the same frequency but with a lower voltage you effectively have more boost window which means you can hit higher clocks more often in a span of time that the boost window is. That equates to less time required to finish bursty workloads and more time that could be spent near idle giving longer battery life.

That’s pretty much all I can keep on topic in my train of thought right now. I feel like I might have forgotten some details but I’m not sure. I’ll most likely be writing about the Coffee Lake 8700k sometime soon so look out for that if you enjoy the technical stuff I write about. Thanks for reading!