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
Load Delta Power Consumption
Power consumption was tested on the system while in a single MSI GTX 770 Lightning configuration with a wall meter connected to the OCZ 1250W power supply. This power supply is Gold rated, and as I am in the UK on a 230-240 V supply, leads to ~75% efficiency > 50W, and 90%+ efficiency at 250W, suitable for both idle and multi-GPU loading. This method of power reading allows us to compare both the power management of the BIOS and the board's ability to supply components with power under load, and includes typical PSU losses due to efficiency.
Each of the Broadwell-E SKUs are rated at 140W, however they vary between 6 cores and 10 cores and with different frequencies. Normally one would assume that the core/frequency ratio would be adjusted to match TDP, but ultimately using more cores can consume more power. We see a distinct increase in power consumption moving up the product stack.
Prime95 Core Loading
For this review, we also looked into peak delta power draw when varying the number of cores using Prime95’s mode for peak power consumption. Prime95 identifies cores with multiple threads and adjusts its loading/pinning accordingly.
Broadwell-E Overclocking
Methodology
Our standard overclocking methodology is as follows. We select the automatic overclock options and test for stability with PovRay and OCCT to simulate high-end workloads. These stability tests aim to catch any immediate issues with memory or CPU errors.
For manual overclocks, based on the information gathered from previous testing, we start off at a nominal voltage and CPU multiplier, and the multiplier is increased until the stability tests are failed. The CPU voltage is increased gradually until the stability tests are passed, and the process repeated until the motherboard reduces the multiplier automatically (due to safety protocols) or the CPU temperature reaches a stupidly high level (100ºC+). Our test bed is not in a case, which should push overclocks higher with fresher (cooler) air.
Overclock Results
Due to time constraints we were only able to overclock the i7-6950X using the MSI X99A Gaming Carbon motherboard. MSI has improved its overclocking options as of late on the Z170 platform to make it easier to use, but our BIOS did not have those most recent updates, particularly for load line calibration. However, our sample hit 4.1 GHz at 1.30 volts before the OCCT load temperatures were prohibitive to move up any further. We saw similar things when testing the mainstream Broadwell parts with Iris Pro, which shows that this sort of overclocking performance might be indicative of the silicon itself.
That being said, speaking with our contacts at various motherboard manufacturers, we're told that 4.1 GHz is a reasonably average processor result for Broadwell-E. Some processors will hit 4.3 GHz on air at around the same voltage, whereas others need up to 1.4 volts, and thus results will depend on the cooling setup used or the thermal characteristics of the silicon. I have also been told that AVX is a different story: for any peak frequency attained normally, AVX overclock stable frequencies will be around 200-300 MHz lower.
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RussianSensation - Tuesday, May 31, 2016 - link
It's a slap in the face when 6850/6900/6950X are also crap overclockers and will get owned hard in games and every day tasks by a $310 6700K. The only CPU that even remotely makes sense is the 6800K. For workstation use case, dual Xeons will smash the 6950X. Heck, it's better to build a 6900K + 6700K in the same case allowing one to be productive and game at the same time. Phanteks makes such cases now. 6950X is just a way to show your status, nothing more.mapesdhs - Thursday, June 9, 2016 - link
Something usually missing from reviews now is an oc'd 4820K, which is annoying because a 4c IB-E on X79 allows for quite a lot of oc headroom given the high rating of the socket and the beefy power delivery available on boards like the R4E, etc. I bet it would give many of the newer CPUs a serious pelting.Drazick - Tuesday, May 31, 2016 - link
Could we have Extreme Edition with Iris Pro + 128MB eDRAM?That would be a great addition (Even only for the 6 Cores Part).
Eden-K121D - Wednesday, June 1, 2016 - link
Iris pro would be useless but i agree with the eDRAM acting as L4 Cachebarleyguy - Tuesday, May 31, 2016 - link
Great review.One possible omission though: You mentioned that the Xeon E-2640 is a better deal as far as price/performance, but there are no Xeons on the benchmark charts. Do you plan to review the E-2640 at some time in the future?
Thanks.
ShieTar - Tuesday, May 31, 2016 - link
That might indeed be a statement which needs to be proven by tests?The 2640 has 10 Broadwell-Cores at a 2.8GHz All-Cores-Turbo, the 6950X should have a 10-core-Turbo of 3.2GHz, so you might argue you get 87.5% of the Performance for ~60% of the CPU cost. But the 2640 does have a slower verified memory speed, which may have a little impact. And its turbo boost settings are defined to hit a 90W TDP, and I don't think you can change that even in a workstation with plenty of cooling available. Add to that the fact that you can overclock to improve the performance of the 6950X, and that the 700$ price difference should be considered relative to the overall system cost, and you probably end up with very similar price-to-performance ratios.
I think the stronger challenger to the 6950X price-to-performance figures is the 2687W v4, which can be had for just over 2k$, and gets you annother 2 cores at almost the same clocks. That's ~16% more performance for ~16% more CPU cost, which translates into less than 10% higher system cost.
samer1970 - Tuesday, May 31, 2016 - link
Hello ,we all know that games dont use more than 8 threads today ...
so to take advantage of an 8 cores or 10 cores CPU in Gaming you should Disable HT (Hyperthreading) and run the gaming test again to compare it against the 4 cores i7 6700K .
and test it with SLI as well to reach the i7 6700k bottleneck !
let me put it more simple ,
The i7 6700K has 4 cores and can oc to 4.4 ghz easy . this CPU will give us 8 Virtual cores comparable to 2.2 GHZ clock for each virtual core .
However the 8 Coresi7 6900K , With the HT Turned OFF , will give us 8 cores @ 4.4 ghz EACH !
Thats double the speed of the 4 cores i7 ! if the game uses 8 threads .
EVEN if we dont OC the 8 cores , it would be 3.2GHZ VS 2.2 GHZ !!!
if you ask why Disable HT ? simple because the game will never use 16 Virtual cores !!! and the advantage is LOST .
Please run the test again for games with HT turned off .
and to stress the CPU more , TEST SLI as well , we want the i7 6700K to bottleneck !
THANKS
oh and Intel Should release i5 Broadwel-E CPU , 8 cores without HT , CHEAPER and BETTER for GAMERS
RussianSensation - Tuesday, May 31, 2016 - link
Nice try but no cigar. 6700K @ 4.8ghz + HT is the optimal gaming CPU. No current game even scales linearly across 6 cores + HT. 8-10 core CPU with a slower architecture would lose badly to an i7 6700K @ 4.8Ghz + DDR4 4000.There is not a chance 6950X @ 4.4Ghz can keep up with 6700K OC.
http://www.techspot.com/article/1171-ddr4-4000-mhz...
By the time games use 8-10 cores, we'll be on PS5/XB2 generation in 2020-2021 and Icelake-E. Broadwell-E 8-10 cores will be outdated.
adamod - Wednesday, June 1, 2016 - link
http://www.pcworld.com/article/3039552/hardware/te...look at the ashes bench
mapesdhs - Thursday, June 9, 2016 - link
Oh grud not here aswell! You've been banging on about this HT thing on toms for ages.