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Intel Core i7-8700K Review



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Trusted Reviews Recommended


  • Huge six-core power
  • Highly overclockable
  • Stable and easy-to-use platform
  • Mighty single-core speeds and gaming performance
  • Cheaper than Ryzen 7 1800X


  • Doesn't compete with Ryzen 1700 or 1700X on price
  • Cheaper 8-core Ryzens offer similar multi-core performance
  • Not compatible with older motherboards

Key Specifications

  • Review Price: £360
  • Six cores, 12 threads
  • 3.7GHz base clock
  • 4.7GHz boost clock
  • Overclockable
  • Intel LGA1151 socket (Z370 only)

What are Intel 8th-generation desktop processors?

For years, Intel has been the establishment of PC enthusiasts. To stretch the current British political metaphor, it was ‘many cores for the few’ people who had enough cash to buy a high-end processor and ultra-expensive motherboard.

This year saw AMD apply a ‘many cores for the many’ attitude, aggressively launching its eight-core Ryzen processors into the CPU market. Prices started at under £350, whereas Intel’s quad-core equivalents were costing around the same. Intel would have to employ some serious price reductions to remain competitive.

AMD was afforded much well-earned goodwill as a result. After all, the company had completely changed the CPU market and blown away much more expensive Intel chips in one fell swoop.

Jumping to today, and Intel has launched what in this narrative can be seen as its direct response to Ryzen. For the first time, consumer-level desktop processors go from four cores to six. Combined with Intel’s reputation for mighty overclocking ability and efficient IPC (instructions per clock figures), this could be seen as the company immediately taking the fight to AMD.

So what does Intel have to offer? For this launch, the company has sent over its two biggest hitters for enthusiast gamers and system builders. The Core i7-8700K with six Hyper-Threaded cores for a total of 12 threads, is Intel’s chip for the most demanding users – those who want to blow a wad of cash for the ultimate in performance.

The i5-8400, on the other hand, is a slightly more sedate six-core processor without Hyper-Threading. This is the sort of chip you’re likely to find on mid-range pre-built gaming PCs. I’ll be covering this in a separate review. Perhaps most exciting is the overclockable Core i5-8600K, another overclockable processor for a much more affordable price of £280.

Related: Everything you need to know about 8th-gen Intel Core

Intel 8th-generation (Coffee Lake) processors – Technology, specifications and chipset

The biggest change between 7th-gen and 8th-gen processors is core count. There’s been a 50% increase in the number of cores from four to six, and the same increase in threads from eight to 12. This is the single-biggest factor when it comes to performance of these new chips, but it isn’t the only enhancement that Intel has applied to these new products.

This increase in cores is reflected in the whole lineup (see the table below). Core i5 chips now all get six cores instead of four, plus i3s get four cores for the first time.

Not only are there a greater number of cores, but there’s an updated underlying architecture. Without going too in-depth, it presents a small step up from the previous generation of desktop processors. Where 7th-gen chips used the Kaby Lake architecture, 8th-gen uses Coffee Lake. Both technologies are derived from 6th-gen Skylake, which used a 14-nanometer production process. Briefly, the smaller the production process, the more transistors you can fit onto a given piece of silicon. The more efficient this process, the more efficient the resulting chip. Consuming less power and creating less heat, this will result in even better performance.

Skylake was a 14nm process; Kaby Lake was known as 14nm+. Coffee Lake comes in as 14nm++. In addition to the modified process, Intel is also touting improved overclocking potential, an improved eXtreme Memory Profile (XMP) and even the ability to modify RAM timings without having to reboot your PC each time.

Before I move onto my initial performance findings, let’s take a look at the full ‘Premium Performance’ (otherwise known as Coffee Lake-S) lineup.

Related: Best Intel processor

Cores/Threads Base clock (GHz) Turbo all cores/one core (GHz) L3 cache TDP Price (EU, inc VAT/USD 1K)
i7-8700K 6/12 3.7 4.3/4.7 12MB 95W €388/$359
i7-8700 6/12 3.2 4.3/4.6 12MB 65W €327/$303
i5-8600K 6/6 3.6 4.1/4.3 9MB 95W €273/$257
i5-8400 6/6 2.8 3.8/4 9MB 65W €192/$182
i3-8350K 4/4 4 N/A 6MB 91W €189/$168
i3-8100 4/4 3.6 N/A 6MB 65W €123/$117

Under test in this first impressions review is the i7-8700K, which sits at the top of the tree. It has a base clock of 3.7GHz and can top out at 4.7GHz. There are six cores, each with 2MB of cache for a total of 12MB. Thermal design power (TDP) is rated at 95W – identical to the equivalent four-core Core i7-7700K from last year. The ‘K’ in its product name denotes an unlocked core multiplier. In other words, this chip should be nicely overclockable.

The i7-8700K doesn’t ship with its own cooler on account of its overclockability. You’ll need to pick an all-in-one liquid cooler or a powerful air cooler to ensure it can cope with a proper overclock. Also, remember to buy a proper set of DDR4 memory; depending on your motherboard, you’ll be able to take your RAM speeds well beyond Coffee Lake’s stated maximum of 2666MHz.

It’s worth looking at the new Z370 chipset as well, since currently this is the only chipset with which you’ll be able to pair your new 8th-generation processor. This is hugely disappointing for those who bought a Z170 or Z270 motherboard only a year or so ago expecting upgrade compatibility, and more so considering the Z370 really doesn’t offer a lot more than its predecessors aside from 8th-gen support. It now supports up to 10 USB 3.1 5Gbps ports, plus RAID on PCI-E-based SSD setups natively – which is nice, but far from essential.

There won’t be any other chipsets available at launch, which means that if you’re buying an 8th-gen processor in 2017 then you’ll have to budget for an expensive motherboard to go along with it.

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