Broadwell-E review: Intel’s ten-core Core i7-6950X tested

Intel’s Extreme Edition, or “E” edition, processors have become a regular landmark in the CPU manufacturer’s schedule over the years, providing overclockers and enthusiasts with something to get their teeth into while waiting for the next-generation architecture. This year’s Broadwell-E line-up follows a well-worn path, offering more performance for those whom the current Skylake chips simply aren’t fast enough.

As with previous Extreme Edition processors, Broadwell-E isn’t based on the most recent iteration of Intel’s CPU architecture, but a tweaked fifth-generation architecture. This year, the headline upgrades are a boost to the core count, with up to ten cores (that’s a massive 20 threads) on the flagship Core i7-6950X and a die shrink that introduces the first 14nm processors to Intel’s Extreme Edition line-up.

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Naturally, all the features you’d expect of an Extreme Edition processor are in place, too. The new processors are all unlocked, allowing for straightforward overclocking, and there’s also a boost in L3 cache for this processor line-up, plus support for quad-channel DDR4 2,400MHz RAM.

Surprisingly, given the reduction in manufacturing process size, the thermal design power (TDP) remains the same as Haswell-E at 140W, although there should be no shock about the lack of integrated graphics. If you’re thinking of stumping up this much for your processor, you’ve almost certainly got a fast graphics card close to hand.

Above, for simplicity, I’ve pitted the top-of-the-range ten-core CPU against the top-of-the-range standard Skylake Core i7 and last year’s Haswell-E flagship. It’s not the only new chip Intel has announced, however; there are also three other Broadwell-E CPUs in the range, from the “cheapest” six-core Core i7-6800K, to the eight-core Core i7-6900K. I’ve listed their specifications in the table below.

	Intel Core i7-6900K	Intel Core i7-6850K	Intel Core i7-6800K
Price	$999 (£692)	$589 (£408)	$412 (£286)
Base frequency	3.2GHz	3.6GHz	3.4GHz
Max Turbo frequency	3.7GHz	3.8GHz	3.6GHz
Cores	8	6	6
Threads	16	12	12
Manufacturing process	14nm	14nm	14nm
L3 cache	20MB	15MB	15MB
GPU	None	None	None
PCI lanes	40	40	28
Memory support	4 channels DDR4-2400MHz	4 channels DDR4-2400MHz	4 channels DDR4-2400MHz
TDP	140W	140W	140W
Socket	LGA 2011-v3	LGA 2011-v3	LGA 2011-v3
Architecture	Broadwell	Broadwell	Broadwell

The most noticeable thing here is the cost of the new ten-core unit. It’s phenomenally expensive: 55% more than the eight-core Core i7-6900K, which is a lot considering you’re only getting 25% more cores. Doesn’t seem like very good value to me.

The only good news here is that, if you’re upgrading from Haswell-E, there’s no need to replace your motherboard. The new Broadwell-E chips use the same Intel X99 chipset as before.

But wait, there’s more. In addition to increasing the core count on its range-topping chip, Intel has introduced a new technology for this generation, dubbed Turbo Boost Max Technology 3.0. Apart from sounding like something out of a shaving advert, this is a very slight tweak to Intel’s existing Turbo Boost tech, designed to improve single-threaded performance over the Haswell-E’s rather disappointing showing.

As with regular Turbo Boost, the new technology gives you more speed in short bursts for simple single-threaded tasks. The difference here is that it allows the CPU to boost higher than the advertised max Turbo Boost frequency, as and when circumstances allow. Turbo Boost Max is also more intelligent than its predecessor, and with the help of BIOS and driver support, it’s able to identify which cores are running the fastest and assign the most intensive tasks to those cores.

Broadwell-E review: Performance

So how does the new chip fare in the performance tests? I ran it through our demanding 4K benchmarks to see how it compares with the previous-generation processor.

At base clock speed, the Intel Core i7-6950X is monstrously fast and, as you’d expect, it outperforms the Haswell-E Core i7-5960X comfortably, posting the fastest multitasking and overall scores we’ve seen from a desktop processor.

That’s an improvement of 14% in the video-editing test, 17% in the multitasking test, and 19% in the overall score. The score to take the most note of here, however, is the single-threaded image editing score, in which the Core i7-6950X provides an enormous performance boost – 67% – over the Core i7-5960X. It looks like Turbo Boost Max is doing its job here.

This is not a chip that’s intended to be left at stock frequency, however; it’s for enthusiasts and tinkerers. And without too much effort we were able to get all ten cores up to 3.9GHz without a hint of instability.

Here, the single-core performance of the Broadwell-E is even more pronounced. Although the 4.3GHz overclock we performed on the Haswell-E back in 2014 was nominally higher, the 3.9GHz Broadwell stomps all over it with an overall score of 280, and leaves Haswell-E – and every other consumer desktop processor – in the dust.

At this point, it’s worth noting that you may need to spend a little extra on cooling. We mated our Core i7-6950X with a Cooler Master Hyper 612 Ver.2, which, even with its large, air-cooled radiator, was only able to keep core temperatures down to 36°C at idle and 84°C under load.

Broadwell-E review: Verdict 

So it’s quick, then. The question is, do you really need all of those extra cores? If it’s the very best performance that you want, and damn the cost, the answer has to be yes.

Broadwell-E, at least in the form of the ten-core Core i7-6950X I’ve looked at here, is an absolute beast, and a huge improvement over the previous eight-core Haswell-E i7-5960X.

The big disappointment is the price. Where previous top-specification Extreme Edition processors have been expensive, they’ve normally clocked in at £800-900. This time, the flagship CPU is £1,300 including VAT, and that’s nearly five times (yes, you read that right: FIVE TIMES) more expensive than the fastest, non-extreme Skylake Core i7 processor available today.

It it worth it? That depends entirely on your perspective: if you have plenty of spare cash, undoubtedly. For everyone else, Broadwell-E may well be an investment too far.

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