The Intel Broadwell-E Review: Core i7-6950X, i7-6900K, i7-6850K and i7-6800K Tested
by Ian Cutress on May 31, 2016 2:01 AM EST- Posted in
- CPUs
- Intel
- Enterprise
- Prosumer
- X99
- 14nm
- Broadwell-E
- HEDT
Broadwell-E Conclusion
Intel’s latest Broadwell-E platform is the next iteration of their high-end desktop strategy, which involves bringing the low-to-mid range professional processors into the consumer market and adding a few features (such as overclocking), but removing others (ECC). For this launch, Intel introduced four processors, ranging from six cores to ten cores and varying in price from $434 to $1723.
At AnandTech we have tested Intel’s Broadwell cores before, both in our Broadwell desktop processor review of the Core i7-5775C and the professional level Broadwell-EP Xeon E5-2600 v4 processor review. We noted a 3-5% increase in clock-per-clock performance compared to the previous generation ‘Haswell’ parts at the time. This review tests all the new Broadwell-E parts for direct comparison to the Haswell parts.
Performance
The move from Haswell-E to Broadwell-E is a change from 22nm to 14nm process technology but the microarchitecture is mostly the same, barring minor adjustments. These adjustments include an improved memory controller (now qualified on DDR4-2400), a faster divider, slightly improved branch prediction, a slightly larger scheduler, and a reduction in AVX multiply latency from 5 cycles to 3 cycles.
Due to this, the performance of the new Broadwell-E parts is somewhat predictable. Adding more cores and adjusting for frequency is a good marker, as is adjusting for the new memory speed. That means a move from the i7-5960X to the i7-6950X gives two more cores at the same frequency, or about 25% more performance. The downside of this upgrade is the price: the i7-5960X was launched at $999/$1049, whereas the new i7-6950X is $1723. That’s a big price increase by any standard.
Turbo Boost Max 3.0: A Troubled Implementation
For Broadwell-E, Intel introduced a new technology called Turbo Boost Max 3.0. With an appropriate driver, BIOS, BIOS settings, and software, this allows the system to pin a single threaded program to the best performing single core at a higher-than-listed frequency. It sounds as if it has potential, but the implementation means that very few users will ever see it.
Firstly, the driver/software implementation is perhaps easily overcome when the driver gets pushed through Windows 10 updates, similar to Speed Shift on Skylake processors which is now fully active. The part where it breaks down is in the BIOS and BIOS settings requirements. Ultimately the BIOS controls which P-states are in play (when the OS selects them), but the BIOS settings can override anything the processor might want by default. Because TBM3 involves an increase in frequency, this requires a number of settings in the BIOS to be enabled. But, because each processor is different, motherboard manufacturers are most likely going to run these options at a very conservative value so none of their users have a bad experience. In the end, whether it's used is going to depend on if the motherboard manufacturers enable it in the first place. In the motherboard we tested, we were told that it was a management decision to have it disabled by default. Because most users never touch the BIOS, especially in a prosumer/professional markets, it will most likely never be used in this case.
We didn’t get time to run a full benchmark suite with TBM 3.0 enabled, and will most likely follow up to see where in our tests it can make the most difference.
Market
The pricing will be prohibitive to most. Many enthusiasts who have played in the HEDT space for a number of years are used to the $999/$1049 price point for the most expensive processor, even when the number of cores has increased. However, this time Intel has decided to increase the top chip's cost by almost 70%. This has complications as to what product is best for prosumers looking to upgrade.
For $1721, if a user wants to invest in the i7-6950X but does not want the overclocking, they can invest in either the 14-core E5-2680 v4 for $1745 giving 40% more cores at a lower power with a slight decrease in frequency, or get double the cores in a 2P system and using the E5-2640 v4 processor: a 10-core 2.4 GHz/3.4 GHz part, running at 90W, for $939. Two of these runs a $1878, which is slightly more but having double the cores available might be the more important thing here. However because these CPUs are not often found at retail, it means that users may have to approach a system builder/integrator in order to source them.
One would assume that Intel is interested in retaining the long term HEDT hold-outs still on Nehalem, Westmere and Sandy Bridge-E processors. These prices (and the overclocking performance) might make these users feel that they should hold on another generation, or invest in Haswell-E. That being said, the low-end Broadwell-E pricing is higher than that of the low-end Haswell-E, which will extend the pricing gap between the mainstream and the high-end desktop platform.
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Witek - Thursday, June 16, 2016 - link
@rodmunch69 - Yeah. I also almost 4 years on 3930K (at 3.2GHz->4.2GHz), which I got for something like 350$ at the time. And I still do not see anything better in similar price bracket. x86 arch is a shit, with limited instruction issue, substandard compilers targeting generic cpus, and power hungry circuits trying to workaround the arch limitations.The prices on these new CPUs are shit, and Intel do that because they do not have competition in high performance x86 market right now. I understand making 14nm chip is more costly than previous generations, but eh, still it is crazy. There is no point of using 14nm for desktop if it doesn't provide substantial performance boost or power saving, at similar price. I am seriously looking into ARM64, Power8, MIPS and other architectures (especially high core counts, or ones still in developement - like Out of the Box Computing Mill CPU), that can break this trend (at least on Linux). SPARC looks like highest performance at the moment, but the prices are crazy as hell. Intel Phi is also interesting for paralellized workloads, but the price is still very high (due to the smaller target market).
Zen will help bring these prices into check. 16 core Zen (32 threads) at 1000$ would be awesome, and will bring all these Intel i7 cpus prices down substantially too.
vivs26 - Tuesday, May 31, 2016 - link
Looking at single threaded and multi threaded performance cant help but be reminded of Amdahl's law. The performance you can extract out of your system is only as much your workload allows you to ....ithehappy - Tuesday, May 31, 2016 - link
I am still on i7 950, just with a GTX970, will it be worth it if I get the 6800K? Or shall I still wait for Skylake-E? Gaming is my main priority, and low power consumption, because mine is on nearly 24x7.rhysiam - Wednesday, June 1, 2016 - link
If all you care about is gaming, get an i7 6700K. There's almost no value proposition in these CPUs anymore unless you absolutely need more than 4 cores. Very few games have been shown to benefit from more than 4 cores at all, and the hyperthreading on the i7 6700K will be there to help if (probably when) games finally start to scale better. The single threaded performance of the 6700K is also significantly better. If you have high end graphics and a 120/144hz display, where CPU performance can sometimes start to matter, the 6700K is actually the faster CPU, and would net you higher fps than any of these overpriced Broadwell-E CPUs.The only argument you could make is that at some point in the future games might start to benefit from 6+ cores. We've already seen in gaming benchmarks of i5s vs i3s vs Pentiums that hyperthreading does a surprisingly good job at mitigating the impact of a game running more threads than you have CPU cores. There's a very good chance that the 4 Core + HT of an i7 6700K will hold its own in gaming for a long time to come. Even if that turns out to not be the case, you'd be much better off in the long run just upgrading your machine when you need it rather than sinking money into a Broadwell-E system now.
mapesdhs - Thursday, June 9, 2016 - link
Re your power consumption, if that's because you care about long term cost, then there's a lot of utility in used hw such as a 3930K. It'll give a very good boost, it's much easier to oc than the later models, it's cheap, the platform supports broad SLI/CF, and it'd take years for the slightly higher power consumption of a 4.8 3930K to wipe out the huge cost saving vs. a 3930K (BIN for 96 UKP on eBay UK atm). It'll also better exploit future improvements in game design that support more cores.If you do want something new though, then rhysiam is right, 6700K or 4790K is fine.
Or go for something inbetween, like a used 4930K (costs a bit more, but higher IPC and some other benefits over SB-E).
However, if you do want something new, then rhysiam is right, the 6700K is plenty, or indeed a 4790K.
asmian - Tuesday, May 31, 2016 - link
Quite apart from cost/performance, the key question for some is whether this last version of Broadwell has had retrofitted the SGX extensions that were introduced with Skylake. Was this feature left out as it wasn't part of the original Broadwell platform? (Preferable) lack of SGX will mean this is the last secure-from-remote-snooping Intel processor release, otherwise the last will unfortunately be Haswell/Haswell-E.Anandtech has been conspicuously silent on SGX and why this is a privacy nightmare for users, unable to monitor or detect exactly what software may be secretly running on their processors due to a by-design inability to snoop on the process in-use memory. The benign use cases usually put forward hardly outweigh the risk of mode-adoption by virii, trojans and user-snooping malware of government origin, able to obfuscate their own remote loading, which would potentially be immune from detection by any means (likely including by the AV and anti-malware industry).
For more on why SGX is of concern read http://theinvisiblethings.blogspot.co.uk/2013_08_0... and http://theinvisiblethings.blogspot.co.uk/2013_09_0...
Please confirm definitively whether Broadwell-E has SGX or not.
Jvboom - Tuesday, May 31, 2016 - link
This is so disappointing. Every time a new release comes out I come on here hoping to justify buying. The numbers just aren't there for the $$.Tchamber - Tuesday, May 31, 2016 - link
Is anyone else disappointed that a new, cutting-edge CPU consumes 10W more than my 2010 i7 970 with the same number of cores? Add to that, prices go up faster than performance does. That makes it nice to see that CPUs don't make much difference in gaming. There are plenty of features I'd like, but I can wait till Zen comes out. In all honesty, I'll probably buy Zen just to support the underdog.krypto1300 - Tuesday, May 31, 2016 - link
Man, and I'm still getting by with my workhorse 1366 platform from 6 years ago. Running a Xeon X5650 @ 3.66GHz , 16GB of DDR31866 and a GTX 970! Everything still runs great! Doom and Project Cars do 1440P @ 60fps no problem!mapesdhs - Thursday, June 9, 2016 - link
A good example that shows the continued utility of what IMO was the last really ground-breaking new chipset release. I can remember reading every review I could find at the time about Nehalem and X58. Not done that since.Btw, are you by any chance using a Gigabyte board? 8)