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Friday | October 15, 2021
Intel Core i7-7700K – Review

Intel Core i7-7700K – Review

Before we head towards ‘Cannon’ later this year, ‘Kaby’ is Intel’s lake of choice. More optimised than original, more refresh than redesign? A lot’s been spoken about Kaby Lake and the breaking of Intel’s “tick-tock” manufacturing cycle. Yet with a Core i7-7700K in-hand, we cleared an LGA 1151 socket, fired up the benchmarks and stopped talking.


Intel Core i7-7700K

The Kaby Lake flagship, the Core i7-7700K is a quad-core processor pegged at a stock speed of 4.2GHz, and boosted to 4.5GHz (compared to the i7-6700K’s 4.0GHz and 4.2GHz). With 8MB of L3 cache, and a TDP of 91W, the similarity to a Core i7-6700K is actually fairly clear; it’s only those clock gains and potential that really set this CPU apart.

That’s true across the range of Kaby Lake parts too, with improvements at the transistor level enabling comparable speed boots. One feature that is different with Kaby Lake is an improved ‘media engine’. Reportedly this will boost 4K handling, although discrete graphics solutions are likely the key handler in an enthusiast’s system.

Little new to speak of then, and hardly surprising given that Kaby Lake’s architecture is near identical to Skylake. But the pure speed of the i7-7700K, and the question of overclocking head-room, hold promise. Let’s see what it delivered.

Test system

We dropped the Core i7-7700K into an Aorus Z270X-Gaming 7 motherboard from Gigabyte. The following made up the rest of our test bed:

  • Samsung 850 Pro SSD
  • ROG Strix GeForce GTX 1070 OC edition 8GB
  • 16GB Crucial Ballistix DDR4-3000 kit
  • Noctua NH-U12S
  • Windows 10 Home Edition
i7-7700K at 4.5GHz

Core i7-7700K overclocked to 4.5GHz, not stock speed.


For chip-to-chip comparisons we benchmarked a Core i7-6700K against the i7-7700K at both a stock and overclocked speed. We chose a modest 4.5GHz overclock as the comparison speed for overclocking, because we know it’s a speed that the i7-6700K performs well at. Of course this in no way means the Core i7-7700K isn’t capable of more – it certainly is; way more. Both processors were overclocked simply by upping the multiplier: from 40 to 45 for the i7-6700K, and 42-45 for the i7-7700K. Voltages were left as default as defined by the motherboard, with the i7-6700K at 1.4v and the i7-7700K at 1.3v.


As you can see our benchmarks are consistent, showing that at stock speeds our Core i7-6700K was simply outgunned. Even with a sizable 500MHz overclock, the 6700K couldn’t beat our 7700K’s stock 4.2GHz. That’s pretty impressive and speaks to extra efficiency found in refinement of the 14nm fabrication process. Given the similarity of Skylake and Kaby Lake, we were a little surprised at how big a difference there was, although to us it vindicates Intel’s decision to optimise for users who want new parts.

It’s also interesting that a modest 300MHz overclock for the i7-7700K did little for its performance. It might be that at 4.2GHz the i7-7700K is sitting at a performance per clock sweet-spot – one only worth ditching for a far higher clock speed than we attempted (if an individual sample allows).

Finally, we did carry out additional benchmarking of both processors at both stock and 4.5GHz speeds in Battlefield 1. In Ultra settings (1080p), and with DX12 enabled, both processors helped consistently deliver over 110fps. There was nothing between the CPUs at either speed – perhaps because our 8GB ROG Strix GeForce GTX 1070 OC edition was somewhat levelling the playing field.

Core i7-7700K – Conclusion

A very strong performer, our Core i7-7700K sample impressed in delivering a clear jump forward from Skylake to Kaby Lake. Doing so demonstrably at stock speeds, we likely haven’t seen the best of it. But our decision to opt for a modest but 4.5GHz overclock was intended to offer clear comparison and it has done just that. Suggestions are that with effective liquid cooling a good 7700K sample can go up to 5GHz; and with full-on liquid nitrogen even higher. Plenty to be interested by if you must have those extra MHz, because clearly this is the new enthusiast king.

With speed generally comes heat. And in those terms the processor acted fairly predictably. It sat at 26 degrees at stock and 4.5GHz while idle, matching the overclocked idle temp of the 6700K. At peak load (Unigine Valley Extreme HD on loop alongside PC Mark 8’s Work benchmarks), the 7700K hit 70 degrees at stock and 79 degrees at 4.5GHz. That’s a decent amount of work; while the 7700K handled it, anyone wanting to ramp up the clock speed even more should have sensible cooling in place. A little warmer than we expected, but not by much.

Ultimately, whether the Core i7-7700K is for you should come down to how much extra performance you need or want. Priced around the same as the 6700K, if you’re building a new system then the 7700K is the obvious choice. However, if you’re running a solid 6700K setup and looking to upgrade, the £300+ cost doesn’t represent anything more than refined performance. With that in mind, if you’re desperate to try and hit 5GHz, then this is likely the processor you’ve been waiting for – so enjoy.

Review Date
Reviewed Item
Intel Core i7-7700K
Author Rating

About Author

Kevin Pocock

Kevin is a tech-lover with over a decade's experience testing, reviewing and writing about all kinds of kit.

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