Take Photo: Review: Intel Core i7-6700K

Thursday, November 5, 2015

Review: Intel Core i7-6700K

Introduction and performance

First the bad news. The all-new Intel Core i7-6700K – which pitches in at around $350 (about £225, or AU$475) – does not tear PC gaming a new one. It's not a render monster like none before. It doesn't take desktop number crunching to a whole new level. Bummer.

Instead, it's yet another Intel processor with four cores, eight threads and a habit of humming along at about 4GHz. Isn't that what Intel's top processors for its mainstream platforms have looked like forever? In fact, it's the way things have been since the arrival of Sandy Bridge back in late 2010.

Of course, we've been complaining about the glacial rate of progress at Intel for so long, you might expect this latest mediocrity to have us pondering the possibility of putting an end to it all by stringing ourselves up with SATA cables. After all, you could say the glacial progress comment is actually a bit kind. Intel has in fact backtracked in recent years courtesy of silliness like dumbed down chip packaging and cooling, along with overclocking that's ever more locked down.

So it's true, we're not exactly blown away by this new chip itself. And yet it's still the most exciting mainstream Intel CPU for years. How so? Let's start with the basics, even if they are a bit boring.

Intel Core i7-6700K

Specification

The 6700K is one of two launch chips representing the new Skylake family of 14nm CPUs – the other is the Core i5-6600K. This i7 and its quartet of unlocked Hyperthreaded cores rocks in at 4GHz nominally with a 4.2GHz Turbo clock. Yup, just 200MHz worth of Turbo boost. Why even bother?

Anyway, it slots into the new LGA1151 socket and thereby hooks into Intel's new 100-series chipsets, the most notable of which for us performance junkies is the Z170, which effectively replaces the old Z97. Graphics-wise, there's an Intel HD Graphics 530 core onboard, and thus not one of the fancy new Iris or Iris Pro solutions. Got that?

Whatever, Skylake is a 'Tock' in Intel's Tick-Tock chip development parlance and that means it's supposedly an all-new processor design on an existing production node, in this case 14nm. Except we've barely seen any of the first 14nm chips, known as Broadwell, on the desktop and now Skylake is go for launch. Put simply, Intel's CPU roadmap has gone completely out of whack.

The other problem, when it comes to improving CPU performance, is that Intel's CPU engineers snaffled up all the low hanging fruit long ago. Then they climbed the branches and grabbed everything else. And now there's almost nothing left. Intel's CPU cores are outrageously optimised.

Benchmarks

Cinebench R15: 915
x264 video encoding (frames per second): 56
Memory bandwidth: 26GB/s
Metro: Last Light (frames per second – minimum in brackets): 37 (23)
Shadow of Mordor (frames per second – minimum in brackets): 53 (37)
Project Cars (frames per second – minimum in brackets): 28 (27)
3DMark: 5883
Maximum overclock: 4.8GHz
Peak platform power consumption: 140W

All this explains why our above benchmark results show such a modest uptick in raw CPU performance. It's all of 4% faster than the existing Core i7-4970K in Cinebench. Bleh. As for video encoding, you're looking at a 6% leap. Hardly exciting.

The game benchmarks are arguably even less dramatic. At the kinds of resolutions that a fairly pricey chip like this is likely to find itself operating, the impact of the 6700K is slim going on none. If you've got a fast Intel Haswell processor or an Ivy Bridge chip, hell maybe even a Sandy Bridge chip, you probably won't feel much subjective difference with Skylake. It's just not a big enough step forward.

We even found that the weirdo chip that is the Broadwell Core i7-5775C has the edge in some game benchmarks, and that's probably thanks to the 128MB of eDRAM, something the new Skylake Ks lack.

Overclocking

The two obvious solutions to this problem, of course, are clockspeed and cores. Faster clocks or more cores would give added punch even if the cores themselves remained essentially the same. The problem is that Intel gave up chasing clockspeed a decade ago and it's simply not under enough pressure from AMD to force it to add more cores to its mainstream chips.

Indeed, some would argue more cores wouldn't help much in most apps including games. But we're not so sure. Build it and they will come has been an effective policy for the PC in years gone by. If six cores for gamers became the norm, game developers would make use of them.

But never mind that. So far, we've painted a picture of an unexciting CPU that's part of a fairly broken CPU launch schedule from Intel. Where the hell does the excitement come in? Platform details and overclocking are the answers.

For starters, Intel has doubled the performance of the DMI interface that links the chipset to the CPU. That means you can hook up a really fast M.2 SSD with four PCI Express lanes to the chipset and get the maximum possible performance out of it. Yay.

Intel 100-series

Massive potential

But the best bit involves overclocking. There are a few changes that are significant and for the most part they are really good news. For starters, there's no more baseclock strap, so you have full access to baseclock overclocking. In other words, on paper you can overclock these things via the bus like the good old days of the LGA775 socket and earlier.

Then there's the voltage regulator that's been taken off the CPU and put back on the motherboard, giving finer control of voltages for different sections of the chip. Finally, don't forget those 14nm transistors, they should be hot for some overclock trot, no?

In the case of this 6700K, the full overclocking potential isn't that spectacular. We've got two 6700K CPUs in-house and one hit 4.8GHz, the other 4.6GHz, albeit the latter was on a different motherboard, which could skew the results, especially as the motherboard is now responsible for voltage regulation.

What's really exciting is that we achieved the same overclocking results using the baseclock as the CPU multiplier. So here's the bombshell – this could mean that the days of buying a cheaper chip and clocking the twangers off it could be about to return. For now, the jury is out. And the 6700K itself isn't hugely exciting. But what it hints at for possible cheaper Intel processors in the near future is utterly tantalising.

Verdict

We liked

The new Core i7-6700K gives enthusiasts a bit more pep and performance, but it's most exciting in terms of overclocking, and the fact that it could herald the return of the good old days when you could buy a less expensive chip and ramp it right up with some good cooling.

We disliked

Our benchmark results were rather underwhelming. Yes, the 6700K offers performance gains, but they're very modest improvements, particularly on the gaming front. If you've already got a fast Haswell or Ivy Bridge processor, you probably won't see much noticeable benefit from Skylake.

Final verdict

The Core i7-6700K might not offer a huge amount over and above existing Intel chips in the performance stakes, but it is a little faster, and fingers crossed, the developments on the overclocking side are a sign of good things to come.