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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JimmiG - Tuesday, May 31, 2016 - link
What's worse than the price premium is that you're also paying for the previous generation architecture.I really don't see why anyone would want one of those CPUs. For gaming and most typical applications, the mainstream models are actually faster because of their more modern architecture and higher clock speeds. If you're a professional user, you should really be looking at Xeons rather than these server rejects.
K_Space - Tuesday, May 31, 2016 - link
Exactly. I think that's the whole point: Intel realizes that -realistically- little profit will be made from these B-Es given the little incremental increase in performance so why not use them as an advert for the Xeons (which they have aggressively been marketing for HEDT not just servers over the last few month). Anyone considering these will consider the Xeons now.Ratman6161 - Tuesday, May 31, 2016 - link
There are a few benchmarks where they do make sense, if and only if you are doing that particular task for your job i.e. an environment where time is money. For the rest of us, if I need to do a video conversion of some kind its relatively rare and I can always start it before I go to bed.retrospooty - Tuesday, May 31, 2016 - link
People belittle AMD because even though Intel has dramatically slowed down the pursuit of speed, AMD still cant catch up. It's actually worse than that though. If AMD were competitive at all in the past decade Intel would still be perusing speed and would be further ahead. Its a double edged sword sort of thing.Flunk - Tuesday, May 31, 2016 - link
Yes, Intel has slowed down for AMD to catch up before. Cough, Pentium 4.retrospooty - Tuesday, May 31, 2016 - link
Yup... and back then AMD took advantage of it. I was the happy owner of a Thunderbird, then an Athlon, then an Athlon X2... Then Intel woke up and AMD went to sleep. For the past decade AMD has been too far behind to even matter. In the desktop CPU space there is Intel and then ... no-one.Flunk - Tuesday, May 31, 2016 - link
You're right, it's totally Intel's fault. They could launch a line of high-end consumer chips that cost the same as the current i5/i7 line but had 2-3X as many cores but no iGPU. They'd cost Intel the same to fabricate. They're the only ones to blame for their slowing sales.khon - Tuesday, May 31, 2016 - link
I could see people buying the i7-6850K for gaming, 6 cores at decent speeds + 40 PCI-E lanes, and $600 is not that bad when consider that some people have $700 1080's in SLI.However, the i7-6900/6950 look like they are for professional users only.
RussianSensation - Tuesday, May 31, 2016 - link
40 PCI lanes are worthless when i7 6700K can reliably overclock to 4.7-4.8Ghz, and has extra PCIe 3.0 lanes off the chipset. The 6850K will be lucky to get 4.5Ghz, and still lose in 99% of gaming scenarios. Z170 PCIe lanes are sufficient for 1080 SLI and PCIe 3.0 x4 in RAID.6850K is the worst processor in the entire Broadwell-E line.
Impulses - Tuesday, May 31, 2016 - link
Well if you're about gaming only you might as well compare it with the 6600K... AFAIK HT doesn't do much for gaming does it? The 6800K isn't much better either when your can just save a few bucks with the 5820K.I feel like they could've earned some goodwill despite the high end price hikes by just putting out a single 68xx SKU for like $500, it'd still be a relative price hike for entry into HEDT but could be more easily seen as a good value.
Are the 6800K bad die harvests or something? Seems dumb to keep that artificial segmentation in place otherwise when HEDT is already pretty far removed from the mainstream platform.
When I chose the 6700K over the 5820K I thought it'd be the last quad core I'd buy, but at this pace (price hikes, HEDT lagging further behind, lower end SKU still lane limited) I don't know if that'll be true.