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Broadwell-E: Intel Core i7-6950X, 6900K, 6850K & 6800K Review

Test Setup & Overclocking

Test System and Processors

Core i7-6950XCore i7-6900KCore i7-6850KCore i7-6800K

Motherboard & Memory

We’re using MSI's X99A Gaming Pro Carbon as the basis for our benchmarks and overclocking attempts. As mentioned previously, this is a refreshed X99-based platform that modernizes Intel's aging chipset a bit with USB 3.1 Gen 2 support, Type-C port connectivity and a U.2 connector for high-end storage.

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If you're new to building PCs, MSI's Game Boost is an interesting one-button overclocking feature. Of course, experienced power users are going to tweak their settings manually, but it's still nice to have options.

One of the most important components of a stable overclock is the right memory. We’re using four 8GB modules of G.Skill Trident Z DDR4-3200 for our X99, X79 and Z170 platforms. This should assure our Broadwell-E overclocks aren't limited by memory.

The only difference between our performance benchmark system and the one for overclocking/power consumption testing is cooling. We don't want to risk hitting a thermal ceiling, so the platform we're tuning employs an open-loop water cooling setup that can get rid of as much as 500W of waste heat. These CPUs shouldn't come close to that number, but you never know...


Ashes of the Singularity2560x1440, Point Lights: High, Glare, High, Terrain Detail Object Level: High, Shading Samples: 16, Terrain Detail Shading Samples: 32, Shadow Quality: High
Bioshock Infinite2560x1440, Ultra quality preset, Light Shafts: On, Ambient Occlusion: Ultra, Object Level of Detail: Ultra
F1 20152560x1440, 4x SSAO, 16x anisotropic filtering, Post-processing options enabled, Shadows enabled, Smoke shadows enabled, Vehicle reflections enabled, Weather effects enabled, Ground cover enabled.
3DMarkFire Strike version 1.1
7-ZipVersion 16.02, LZMA2 method, Ultra compression, 4.52GB workload, mixed file types
BlenderVersion 2.75a, Cycles engine, BMW benchmark
CinebenchVersion R15, Single- and multi-threaded CPU benchmark
HandBrakeVersion 0.10.2, x264, Constant quality: 20, variable bit-rate
LAMEVersion 3.99, .wav to .mp3 conversion, 160 Kb/s fixed bitrate
PCMark 8Version 2.7.613, Hardware acceleration enabled, Adobe Creative Cloud and Microsoft Office suites

Overclocking & Stability

Our overclocking methodology includes increasing each CPU's clock rate until we discover the maximum for a fully utilized processor and even faster Turbo Boost settings for each core. We also adjust voltages as-necessary to achieve a balance between stability and waste heat, since this directly affects cooling.

With a configuration that boots successfully, we run different load scenarios to verify stability. After completing Aida64’s integrated stress test (CPU, FPU, cache), the system is faced with workloads created by a Creo 3.0 SPECapc run, 4K video compression using the Adobe CC Media Encoder, a Witcher 3 sequence, Prime95 and AVX.

A clock rate configuration is only considered successful if those workloads finish without any errors and within reasonable voltages. Before we get to the results, here’s a table with our test system’s technical specifications:

Power Consumption Test Setup
Test MethodContact-free DC Measurement at External Auxiliary Power Supply Cable Direct Voltage Measurement at Power Supply Real-Time Infrared Monitoring and Recording
Test Equipment2 x Rohde & Schwarz HMO 3054, 500MHz Digital Multi-Channel Oscilloscope with Storage Function 4 x Rohde & Schwarz HZO50 Current Probe (1mA - 30A, 100kHz, DC) 4 x Rohde & Schwarz HZ355 (10:1 Probes, 500MHz) 1 x Rohde & Schwarz HMC 8012 Digital Multimeter with Storage Function 1 x Optris PI640 80Hz Infrared Camera + PI Connect
Water CoolingPump: Alphacool VPP655 (Undervolted, 50 percent)CPU Cooler: Lian LiReservoir: Phobya Radiator: Alphacool, 24cm (6cm thickness)Fan: 2x 12cm Noiseblocker eLoop, PWM controlled (up to 1500 RPM)


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Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.