Haswell-E or Broadwell-E? Intel i7-5960X vs. i7-6900K vs. i7-6950X

Intel-Broadwell-E

What is the best high-end CPU? The 3 best consumer-grade options are the Broadwell-E i7-6900K and i7-6950X, and the older Haswell-E  i7-5960X. We previously recommended the i7-5960X over the newer i7-6900K in our build guide for NVIDIA’s GTX 1080, because of the older CPU’s superior overclocking potential. Here we will compare the pros and cons of these CPUs in more detail, so that you can make the best choice.

The Line-Up

All of these are extremely high-end CPUs. They all retail for $1,000+, fit into the LGA 2011-v3 socket X99 platform, and use DDR4 RAM.

These processors are for enthusiasts and professional workstation users. All three chips are unlocked and can be overclocked.

That is where the similarities end. Let’s examine the specifications:

i7-5960X i7-6900K i7-6950X
Family Haswell-E Broadwell-E Broadwell-E
Chipset X99 X99 X99
Lithography 22 nm 14 nm 14nm
Memory Support DDR4-2133 DDR4-2400 DDR4-2400
Base Core Clock 3.0 Ghz 3.2 Ghz 3.0 Ghz
Max Turbo Core Clock 3.5 Ghz 4.0 Ghz 4.0 Ghz
# Cores 8 8 10
# Threads 16 16 20
Cache 20 MB 20 MB 25 MB
TDP 140W 140W 140W>
Recommended Price $1049 $1109 $1743

(source: http://ark.intel.com/)

The Broadwell-E family released earlier this year, while Haswell-E was released back in 2014. The Broadwell processors support faster memory. While all three chips support XMP profiles and memory overclocking, baseline 2400Mhz support is nice. The newer i7-6900k also features a higher base and turbo clock than its older cousin, the i7-5960X.

The 6950X costs $600 more than either Haswell’s 5960X or Broadwell’s 6900K. This puts it out of reach for many of us, but that extra money provides an additional 5MB L3 Cache, and two more cores (four extra threads). These can provide a large performance increase if your software can take advantage of the extra resources. It borders the Server/Workstation segment both in price and features, and is designed for enthusiasts looking to get the maximum performance possible.

Overall Performance

According to AnandTech, the i7-6900k is better than the i7-5960X at single threaded applications by 9%. The 6950X does fall slightly behind the 6900k in these benchmarks, but still manages to stay ahead of its predecessor. High-end Skylake chips are still the top single-threaded performers to date by at least 13%.

The i7-6950X is better than any other consumer CPU in multi-threaded applications that can take advantage of all 10 cores. It bests the 6900k by 20%, and has a whopping 38% greater CineBench score than the 5960X. In multi-threaded applications, the 6950X is in a class of its own.

Overclocking Capabilities

The 5960X is still the best overclocker.

It is still possible to gain generous overclocks of up to 4.3GHz depending on the silicon lottery with the 6950X. Even so, the 5960X at the same clock speeds is more power efficient than the 6900K at base clock. TomsHardware showed that at an overclock of 4.0GHz, the 5960X used 124W under load. Despite it being only 0.8GHz of an overclock instead of a full gig, the 6900K managed to draw 148W at 4.0GHz.

The gap only grows wider as the overclock increases. Overclocking Broadwell-E requires a beefy power supply and cooling.

Gaming Performance

At base clocks, Broadwell-E processors are better by 0.5-2fps at best in most games according to AnandTech‘s benchmarks. If gaming is your only desire, all three CPUs essentially perform the same. However, if you want to overclock, the 5960X gains the advantage. Most games don’t effectively use more than a few threads, and thus depend on higher clock speeds to perform better.

Winner: Depends on your needs

For the intended audience of enthusiasts and professionals needing as much processing power as possible out of their workstation who don’t want to mess with overclocking, the newer chips are the best choice. The 6900K and 6950X have slightly better performance than the older 5960X. In any application that can take advantage of the the extra cores of the 6950X, such as video editing, it is the clear winner. However, for anyone who wants to overclock, the 5960X becomes a better choice than the 6900K at similar prices.