Intel’s i7-7700K Kaby Lake CPU follows-up on Skylake with a microarchitecture that is largely identical, but with key improvements to the process technology. Through what Intel has dubbed “14nm+,” the new process technology has heightened fins and widened the gate pitch, both serving as key contributors to the increased frequency headroom on the 7th Generation Intel Core CPUs. Other key changes, like enablement of finer-tuned frequency switching and AVX settings, theoretically offer better responsiveness to current demand on the CPU. As with most active frequency tuning, the idea is that there’s some power efficiency benefit that is coupled with better overall performance by way of reduced latency between changes.
Kaby Lake CPUs are capable of switching the clock speed at a 1000Hz rate (or once per millisecond), and though we’ve asked for the minimum frequency adjustment per change, we have not yet received a response. AMD recently made similar mentions of this sort of clock adjustment on Ryzen, using the upcoming Zen architecture. More on that later this week.
Today’s focus is on the Intel i7-7700K flagship Kaby Lake CPU, for which we’ve deployed the new MSI Z270 Gaming Pro Carbon ($165) and Gigabyte Z270 Gaming 7 ($240) motherboards. For this Intel i7-7700K review, we’ll be looking at thermal challenges, blender rendering performance, gaming performance, and synthetic applications. Among those, FireStrike, TimeSpy, and Cinebench are included.
The thermal results should be among the most interesting, for once, though we’ve also found Blender performance to be of noteworthy discussion.
Product availability should begin on January 5, with the official launch today (January 3) for the Intel 7th Gen Core CPU products. Note that some products will not be available until later, like the i3-7350K, which is expected for late January. The i7-7700K will be here once it's available.
There are more than 40 SKUs for the 7th Generation Kaby Lake CPUs, when counting Y-, H-, S-, and U-class CPUs. Starting with the specifications for the 7700K, 7600K, and 7350K CPUs (i7, i5, i3, respectively):
Intel Core i7-7700K vs. i5-7600K, i3-7350K Specs
|Intel Kaby Lake K-SKU CPUs|
|IGP||HD 630||HD 630||HD 630|
|Intel Smart Cache||8M||6M||4M|
The 1,000-unit pricing for the i7-7700K will be $339, with the i5 and i3 K-SKU CPUs at $242 and $168. For reference, the cheapest i5 Kaby Lake CPU will be the i5-7400 (non-T), priced at $182 – so about a $14 jump from the i3-7350K and i5-7400. We’ll be interested to benchmark this matchup once we have both units.
The 7350K is Intel’s first unlocked i3 CPU, making the same overclocking provisions as have been granted with the i7 and i5 K-SKU CPUs. You will be given access to multiplier and BCLK manipulation through supporting platforms – Z270, in this instance.
We’ll be curious to see how the 7350K overclocks, since its limited 2C/4T configuration may permit higher frequencies without the usual requirement of toggling hyperthreading or disabling cores (as more extreme overclocks require).
Speaking of, Kaby Lake has generally been an excellent overclocker for us – we’ll get to that later in this review – and that’s largely because of the changes made in 14nm+, accounting for the additional 200-400MHz clock-rate out of the gate.
With our focus on the 7700K, we’re looking at a somewhat traditional 4C/8T CPU, but with a higher frequency than previously. Cache remains the same as on the 6700K, both at 8MB total.
Before carrying on with overclocking and chipset discussion, here are the tables recapping the i5 and i3 specs:
Intel Kaby Lake Core i5 & i7 Non-K CPU Specs
|Intel i5 & i7 non-K Kaby Lake Specs|
|IGP||HD 630||HD 630||HD 630||HD 630|
|Intel Smart Cache||8M||6M||6M||6M|
As always, the primary difference between these CPUs and the above SKUs is the lack of overclocking support. A few other changes are also present, like the lowered TDP (65W from 91W). All totaled, Intel’s TDP has remain largely the same this generation from Skylake. Keep in mind that TDP is not the same as power consumption. We’ll demonstrate this in our thermal analysis section, where we show the impact of voltages on the power consumption and temperature of the package.
Frequency is the other main point of difference, with the 7700 non-K dropping to 3.6GHz base, or 4.2GHz Turbo Boosted. This is from 4.2/4.5GHz on the 7700K under review. The i5-7600 non-K also falls in frequency down to 3.5/4.1GHz from 3.8/4.2GHz. Once we hit the i5-7500, dynamic frequency drops 50MHz, core frequency drops to 3.4/3.8GHz, and price falls below $200 – now at $192 1ku for the i5-7500.
And a quick update on the i3 family:
Intel Kaby Lake i3 Non-K Specs
|Intel i3 Kaby Lake Specs|
|IGP||HD 630||HD 630||HD 630||HD 630||HD 630|
|Intel Smart Cache||4M||4M||3M||4M||3M|
Kaby Lake Architecture & Frequency Behavior Updates
Like everyone else, including AMD with Ryzen and both GPU vendors with Pascal/Polaris, Intel is now moving to better leverage frequency shifting based upon workload. This isn’t new with Kaby Lake, but has received renewed focus.
SpeedShift isn’t new to Kaby Lake. SpeedShift and Intel’s frequency switching handle clock-rate at a hardware level, bypassing overhead created by the host. This means that the CPU is capable of governing its performance based on the current workload, down-clocking when high frequencies are unnecessary and “up-clocking” when load demands. CPU P-States are checked and modified at a 1000Hz refresh rate.
Intel has also been touting the phrase “BCLK awareness” with regard to Kaby Lake, which boils down to implementing a better volt-frequency curve. Like the major processing architectures we discussed through 2016, volt-frequency curves are simple in concept: They allow for frequency to update versus a specified voltage, sort of like a reference table, furthering efforts to use the lowest functional voltage at each frequency. This is primarily a power saving feature.
Even with the curve, motherboard manufacturers still hold control over volt-frequency tables that are referenced under “auto” settings. Our Gigabyte board, for instance, was supplying far more voltage than VID actually requests, resulting in the high temperature values that we’re reporting under some conditions (see thermal benchmarks, later in this review).
What About Xeon CPUs?
Of course, a new architecture also brings updates to the Xeon series of workstation CPUs. As Xeons frequently find themselves in gaming and hybrid gaming/production machines, we’ve listed the specs of the E3-1535M v6 and E3-1505M v6 CPUs below:
|Intel Xeon Kaby Lake Specs|
|GamersNexus.net||E3-1535M v6||E3-1505M v6|
|Frequency (1C Turbo)||4.2GHz||4.0GHz|
|Frequency (2C Turbo)||4.1GHz||3.8GHz|
|Frequency (4C Turbo)||3.9GHz||3.6GHz|
|IGP||HD P630||HD P630|
|Intel IGP Frequency||350/1100MHz||350/1100MHz|
|Intel Smart Cache||8MB||8MB|
Both units are equipped with the P630 IGP, unlike some previous Xeon SKUs that have gone without the integrated graphics. Thus far, it doesn’t look like Xeon will remain the secret, cheaper alternative to i7 CPUs for gaming machines. The 1535M v6 has a 1ku price of $623, with the 1505M v6 at $434.