Intel Core i7-6950X Broadwell-E Processor Review

Introduction Intel has been dominating the HEDT market for a considerable amount of time as prosumers' hefty multi-threaded workloads require additional cores which the mainstream platform cannot accommodate. The company's long-term strategy appears to revolve around the idea that 4-cores, 8-threads is ample for enthusiasts and anyone yearning for 6, 8 or even 10-core processors should move onto the professional 2011-v3 platform. An interesting pattern emerged when the i7-6700K launched in the UK as it hovered around the £320 mark and remained within touching distance of the i7-5820K. This particular chip contains 6-cores and has a good thermal tolerance to achieve superb overclocks although the PCI-E lanes are restricted to 28. Of course, this is the most affordable Haswell-E CPU Intel has produced and the higher end offerings which utilise 40 PCI-E lanes targets less gaming-orientated scenarios. In particular, the i7-5960X launched at $999.99 and became the company's first 8-core processor outside of the Xeon family. The entire Haswell-E range was based on a 22nm lithography and officially supported up to 2133MHz of quad-channel DDR4 memory. Intel has since updated the X99 platform in the form of Broadwell-E which includes the i7-6800K, i7-6850K, i7-6900K and i7-6950X. This time, the manufacturing process has changed to 16nm with tri-gate 3D transistors being deployed. Instead of analysing the entire line-up, we've decided to focus on Intel's new flagship and investigate its place in history as the first 10-core processor to grace the desktop. As you can see below, the i7-6950X features a 3.0GHz base frequency, maximum turbo of 4.0GHz, 25MB of level 3 cache and 10-cores/20-threads setup. Not only that, the processor has a 140W TDP and slots into any 2011-v3 motherboard on the proviso that the BIOS has been updated. This backwards compatibility with existing motherboards is fantastic because they're much more expensive than their Z170 counterparts. Priced at a whopping £1419.99, the i7-6950X is a serious investment and one that I predict many professionals will struggle to justify. Clearly, the product is niche and a major price increase compared to the i7-5960X. Is the additional 2-cores worth the extra? Let's find out! Specification What's New? Here we can see the i7-6950X's die map which outlines the how the 14nm process is compiled. Please note, Broadwell-E isn't a major architecture shift and revolves around a die shrink with a few added features. Nevertheless, the die is very impressive and Intel doesn't really need to innovate in this area considering the hard work has already been done. The latest X99 motherboards natively support Thunderbolt 3.0 which provides the end-user with a wealth of possibilities such as daisy chaining multiple high-resolution displays and connecting extremely fast external drives. As shown by the slide below, Thunderbolt 3's 40Gbps bi-directional bandwidth is eight times faster than USB 3.0. When it comes to overclocking, Intel has incorporated three new features which offer greater flexibility. On older processors, users could only set a specific multiplier for each core. Saying that, per core overclocking isn't exclusive to Broadwell-E so I'm a little perplexed by this slide. For example, Z170 motherboards support this feature and you can easily tweak the multiplier for each core. The VccU voltage control is useful to attain higher frequencies from the CPU's ring and designed for extreme overclocking cases with LN2. Additionally, the AVX ratio offset analyses instructions sets which can cause the processor's TDP and temperatures to skyrocket through extra voltage. Thankfully, the particular AVX instructions which are the root cause of this now run at the optimal frequency and offer a better balance. Another important element to discuss is the Turbo Boost Max 3.0 Technology. This latest version allows Intel to identify the best performing core at the factory and it's flagged with a * in the BIOS. Interestingly, this core can run at a much higher frequency than the weaker cores which result in better single-threaded performance. Also, the Turbo Max 3.0 Technology automatically configures the affinity in applications to prioritise the fastest core. Out of all the new additions, this is probably the most impressive and allows the 10-core configuration to fare reasonably well in single-threaded workloads which prefer higher clock speeds. Packaging and Accessories Since the unit received for review purposes is an engineering sample kindly provided by ASUS, there's no retail packaging or accessories. Even if you purchase the processor from an official outlet, don't expect to receive a bundled heatsink as per usual with enthusiast Intel products. I don't have any major issues with this considering the Intel stock heatsink is extremely basic and if you have the funds to afford a processor just under £1500, selecting an aftermarket cooler isn't going to break the bank. The i7-6950X has a different IHS design compared to the i7-5960X and includes more angular edges. Apart from that, the appearance is fairly similar and you'd expect that given the backwards compatibility with existing 2011-v3 socket motherboards. Intel's new flagship is much thinner than its predecessor measuring in at 1.12mm. To put this in perspective, the i7-5960X is approximately 1.86mm thick. The CPU's contact points remain largely unchanged but there is an increase in the number of SMDs. Unfortunately, during the time of review, I experienced a few teething issues with the i7-5960X which meant that had to take priority instead of some comparison photos. Test System and Methods Before we delve into any testing we would like to take this opportunity to overview our test system. Test System Z87 Motherboard - ASUS Maximus VII Ranger RAM - 16GB Crucial Ballistix Sport XT (2 x 8GB) DDR3 1866MHz (10-10-10-30) CPU Cooler - Thermaltake Water 3.0 with Gelid GC-Extreme Graphics Card - Gigabyte G1 Gaming GTX 980Ti Power Supply - BeQuiet Dark Power Pro 850 Watt Main Storage Drive - Crucial M550 512GB Chassis - Lian Li T80 Test Bench Displays - U2868PQU 4K Operating System - Windows 10 Pro 64 Bit Z170 Motherboard - ASRock Z170 Extreme7+ RAM - 12GB (4 X 4GB) Crucial Ballistix Sport DDR4 2400MHz (16-16-16-39) CPU Cooler - Thermaltake Water 3.0 with Gelid GC-Extreme Graphics Card - Gigabyte G1 Gaming GTX 980Ti Power Supply - BeQuiet Dark Power Pro 850 Watt Main Storage Drive - Crucial M550 512GB Chassis - Lian Li T80 Test Bench Displays - U2868PQU 4K Operating System - Windows 10 Pro 64 Bit X99 Motherboard - ASUS STRIX GAMING X99 RAM - 32GB (4 X 8GB) Crucial Ballistix Sport DDR4 2400MHz (16-16-16-39) CPU Cooler - Thermaltake Water 3.0 with Gelid GC-Extreme Graphics Card - Gigabyte G1 Gaming GTX 980Ti Power Supply - BeQuiet Dark Power Pro 850 Watt Main Storage Drive - Crucial M550 512GB Chassis - Lian Li T80 Test Bench Displays - U2868PQU 4K Operating System - Windows 10 Pro 64 Bit Games Used Ashes of the Singularity (DirectX 12) Rise of the Tomb Raider Test Software 3DMark - available here AIDA64 Engineer - available here Cinebench - available here Compubench - available here CPUID HWMonitor - available here CPU-Z - available here Handbrake - available here Prime95 - available here WinRAR - available here WPrime - available here Test Procedure Here at eTeknix, we endeavour to disclose key information regarding the benchmarking process so that readers can quantify the results and attempt to replicate them using their own hardware. When it comes to CPU reviews, the benchmarks are pretty self-explanatory although there are a few exceptions. Please note, we prefer to re-test each CPU within a product's performance range to ensure the results are completely accurate and reflect any changes to our samples over time or enhancements via graphics drivers. This means we now include fewer results, but they are more accurate and easier to decipher. As always, your choice of motherboard, the silicon lottery and other factors can yield different numbers and there's always a margin for error when using software. Therefore, your experience may vary. Saying that, each benchmark is run at least three times and the average figure is taken to try to reduce the effect of hardware variation. Any important details regarding the benchmarks will be listed below. Handbrake To stress processors to their absolute limit and accurately judge performance in video editing workloads, we transcode a 7.7GB compilation of gaming footage. This particular file is freely available from here. The captured footage is 22 minutes and 12 seconds long, has a bit rate of 50.1 Mbps and uses the Advanced Video Codec. Additionally, the video runs at a constant 30 frames-per-second and opts for a 3820x2140 (4K) resolution. Once loaded into Handbrake, we transcode the 4K MP4 to a 1080p MKV file. Both the average frames-per-second and time elapsed are recorded to provide our readers with an idea of estimate video transcoding project times. CPU Benchmarks - Ashes of the Singularity, Cinebench, Handbrake, WPrime and WinRAR Ashes of the Singularity The Ashes of the Singularity CPU benchmark provides an excellent indication of a processor's multi-threaded performance and I've been reliably informed that the game is capable of utilising the i7-6950X's 10-cores to their full potential. At stock settings, the CPU outperforms the i7-5960X by a small margin and manages to uphold a good lead over the i7-5820K. Once overclocked, the processor records the highest CPU frame-rate thus far and just edges the previous flagship while having a 100MHz deficit. Of course, clock speed isn't everything and instructions per clock (IPC) improvements should be taken into account. Cinebench R15 In Cinebench, the i7-6950X absolutely destroys the competition when running the multi-threaded benchmark and greatly benefits from the 10-core configuration. The default frequency is able to easily pull ahead of an overclocked i7-5960X and offers a fantastic performance boost. When overclocked to 4.3GHz, the i7-6950X's multi-threaded capabilities almost defy belief and upon seeing the result, I couldn't stop smiling. The 2212 score is mindblowing and exceeded my initial expectations. As you can see, this makes the processor in a league of its own. On the other hand, the number of cores inhibits the CPU's single-threaded performance and mainstream options like the i7-6700K fare much better. Even the older i7-4770K attains a better score than Intel's new flagship at stock. Saying that, the overclock improves the performance considerably. Handbrake The CPU's extra 2-cores come in handy when transcoding a 4K video file and reduces the time taken to a large degree versus the i7-5960X. In many industries, time is money so this may be enough of a reason for certain people to consider the processor as a worthwhile investment. Clearly, the CPU is tailored towards intense video workloads and it's possible to achieve much quicker rendering times. WPrime As expected, the i7-6950X excels during the WPrime Pi calculation benchmark and at stock values it's able to defeat an overclocked i7-5960X. This is an impressive feat and emphasises the additional performance possible from Intel's premium desktop processor. Also, the 4.3GHz overclock extends its lead even further and becomes the first product to complete the 32M task in under 3 seconds. WinRAR Once again, the CPU performs admirably and compression times are greatly reduced compared to Intel's previous flagship. As you can see, the i7-6950X's default setup matches an overclocked i7-5960X while manually configuring the processor to 4.3GHz results in some fairly impressive gains. Memory Benchmarks - AIDA64 Memory Bandwidth In terms of memory bandwidth, the i7-6950X outputs astonishing numbers and the write rate dramatically improves. Now the write speed surpasses 60,000 even when using a fairly modest 2400MHz quad-channel kit. The read and copy performance isn't as much of a monumental change which is to be expected. Nevertheless, Intel's latest flagship fares very well in the memory stakes. Memory Latency The processor's memory latency is extremely close to the i7-5960X despite offering much higher bandwidth. OpenCL Benchmarks - Compubench Compubench CL Unfortunately, the latest version of Compubench wouldn't function correctly with any 2011-v3 processor. Therefore, it wasn't possible to test the CPU's OpenCL performance. This also applies to Luxmark which focuses on GPU benchmarking instead of the CPU. Since the X99-based products rely on a discrete GPU, manually selecting the CPU wasn't feasible. Discrete GPU Benchmarks 3DMark At stock settings, the i7-6950X posts a fantastic 3DMark Fire Strike score which outperforms an overclocked i7-5820K and i7-5960X. Overclocking the CPU brings the score beyond 17200 and just edges an i7-5960X running at 4.4GHz. Honestly, there's not a huge difference between the i7-6950X and i7-5960X unless both products have been overclocked to their maximum potential. Ashes of the Singularity Unlike many games on the market today, Ashes of the Singularity has excellent multi-threaded support. This is evident in the data below which shows products with extra cores performing better. Saying that, the gap between X99 processors is almost non-existent and within a margin of error. Furthermore, overclocking the CPU yields very minor gains. Rise of the Tomb Raider A similar pattern emerges in Rise of the Tomb Raider and the performance remains relatively GPU bound. While there is a difference between various Intel processors, it's mostly inconsequential and varies dramatically depending on multiple runs. It's somewhat surprising to see the i7-5820K on top, but you have to remember that the products tested don't inhibit the game's performance in a noticeable way apart from the ageing i7-4770K. Overclocking Overclocking When it comes to overclocking, I like to employ a similar strategy to the i7-5960X to provide a more direct comparison. As a result, the overclocking mainly revolves around a multiplier increase as altering other elements such as the BCLK and CPU strap didn't extend the maximum stable overclock even further. As previously mentioned, you can prioritise the frequency for the highest performing core and dynamically set different multipliers. However, I decided to resort to a more general overclock setting and ensure the frequency on all cores was perfectly usable. By default, the best core can turbo up to 4.0GHz and after taking the 10-core configuration into consideration, I aired on the side of caution. Initially, the multiplier was set to 42 with a voltage of 1.276V which caused the test system to freeze. After performing further testing, the sweet spot for 4.2GHz was 1.289V and then worked towards a higher frequency. Idealistically, I hoped to reach 4.4-4.5GHz given the hefty water cooling hardware and thought this equipment would be able to cope with the extra thermal demands at higher voltages. To my complete dismay, 4.4GHz just wasn't achievable due to the CPU reaching its TJ Max and throttling under stress. When you surpass 1.3V, the temperatures skyrocket which means obtaining a stable frequency beyond 4.4GHz is down to the silicon lottery. Eventually, I settled on a 4.3GHz figure and applied 1.305V. Please note, even with 1.305V, the CPU was on the bleeding edge of stability and I wouldn't recommend it for 24/7 usage. Of course, overclocking so many cores is going to be a challenge and this is reflected in my own personal experience. Power Consumption and Temperatures Power Consumption During idle power states, the processor while operating in its stock configuration is reasonably efficient and consumes less power than the i7-5960X. However, the improvement is remarkably small and any reductions in power saving by using a smaller manufacturing process seems minimal. Saying that, the overclocked TDP is less than the i7-5960X under load and by a decent amount. This is much more promising and outlines the improved efficiency Broadwell-E brings in extreme usage scenarios. Temperatures The i7-6950X is remarkably cool when running at the base specification and records a slightly lower temperature than its predecessor. On the other hand, overclocking the processor at 1.3V or higher massively increases the thermal loads to levels which you shouldn't be using on a permanent basis. Annoyingly, the CPU doesn't have a gradual transition when setting a higher voltage to maintain stability and struggles to stay within the thermal limits even when paired with exceptionally high-end cooling. Final Thoughts Pricing At the time of writing, Intel's latest flagship desktop processor retails for an eye-watering £1419.99 from eBuyer.com. Please note, this is the cheapest price I've seen for some time and it's been quite common for stores to charge near the £1500 mark. Of course, this is an absurd amount of money, but you have to remember that it's not a mass market product and designed for professionals who rely on complex multi-threaded workloads to please clients. Theoretically, it could be argued that there is some value to the i7-6950X providing you're working with an application which can take advantage of the full 10-cores. However, the Intel Xeon E5-2640 v4 is the much better option in my opinion unless you have to keep using the X99 platform. For example, this Xeon chip can be procured for £916.09. utilises the same 10-core/20-thread configuration and has 25MB of level 3 SmartCache. The i7-6950X does have some advantages since the Xeon processor doesn't support multiplier overclocking, has a base frequency of 2.4GHz and official memory bandwidth support ends at 2133MHz. It's possible to overclock the Xeon model using the BCLK but this is going to be quite limited compared to the i7-6950X. One major benefit the Xeon has is you can buy two and substantially increase your workstation's compute performance. Whether you feel the i7-6950X's extra features are worthwhile is down to your own personal requirements but I struggle to understand why this new 10-core has received such a price hike over the previous flagship. Overview As Intel's first 10-core desktop processor, the i7-6950X is a landmark product and continues the company's trend of increasing the core count on a fairly regular basis. This latest feat of engineering offers astounding multi-threaded performance and exhibits a significant lead over the previous flagship in professional applications. Of course, the number of programs able to utilise the extra cores is small and the i7-5960X should be ample for most usage scenarios. Saying that, in extreme circumstances where the longer rendering times cost money, the higher retail price might be justified. Personally, I'd still go down the Xeon route and make a few compromises when it comes to raw frequency. The i7-6950X provides superb quad-channel memory bandwidth and the write speeds are well ahead of the i7-5960X. When paired with a set of DIMMs running at a modest 2400MHz speed, the write rate went from 47,972 on the i7-5960X to 60,744 on Intel's 10-core processor. This is a substantial improvement and the added write bandwidth can be useful in specialised workloads. Typically, single-threaded performance is quite disappointing on processors sporting a high core count and it's challenging to achieve the sort of frequencies possible on a chip like the i7-6700K. Intel has tried to alleviate these concerns with the Turbo Boost 3.0 Technology which outlines the best performing core and automatically increases the clock speed from 3.0GHz to 4.0GHz. Despite this, it didn't seem to make a huge difference compared to the i7-5960X and i7-5820K and remained behind the i7-6700K in single-threaded tasks. I do think it's a fantastic inclusion which pushes the single-core performance of processors mainly designed for multi-threaded performance slightly higher. In terms of overclocking, the headroom is extremely limited and going beyond 4.3GHz requires impeccable cooling hardware. Even when paired with a 360mm closed loop liquid cooling solution, the temperatures rise at a frantic pace and it's unlikely that you'll be able to keep the overclock stable. From my own experience, 1.3V or above is required to reach 4.3GHz and this puts a huge strain on the processor's thermal output. As a result, the temperatures hit an average of 91C and almost failed the benchmark. Clearly, your mileage may vary but it's essential to invest in the right cooling apparatus if you want to overclock the CPU and maximise its potential. Selecting above 1.3V results in a huge power consumption spike but it's still lower than the i7-5960X. Once overclocked, the processor excels and posts very impressive results. Therefore, it's worth investing the time to overclock the CPU to at least 4.2GHz if possible. Intel has incorporated a number of other features to aid overclocking such as the AVX ratio offset and VccU voltage control. This makes the i7-6950X a great option for professional benchmarkers and users wanting to explore the chip's performance with LN2. Pros AVX ratio offset balances performance demands Compatible with existing 2011-v3 motherboards after a BIOS update Extraordinary multi-threaded performance Good stock temperatures Memory writes much faster than i7-5960X Rudimentary overclocking procedure Thunderbolt 3.0 support Turbo Boost 3.0 Technology offers great flexibility VccU voltage control is designed for LN2 overclocking Cons Extreme performance comes at an extreme price Intel Xeon E5-2640 v4 is significantly cheaper Neutral Major thermal increase beyond 1.3V but expected given the 10-core configuration "The Intel Core i7-6950X is capable of unbelievable multi-threaded performance and offers a good boost over the previous desktop flagship providing applications support the extra 2-cores. Saying that, the Intel Xeon E5-2640 v4 is a more enticing proposition unless you have to retain an existing X99 configuration." Intel Core i7-6950X Broadwell-E Processor Review Thank you ASUS for providing us with this review sample.