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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michael2k - Tuesday, May 31, 2016 - link
Zen doesn't exist, yet, so cannot compete at all.When Zen does exist, however, AMD would literally win a Darwin Award if they offer more than a 10% discount for parts that perform similarly.
In other words, if Zen is capable of powering a 10 core part that offers 90% of the 6950X performance, expect it to cost $1,550. If it offers 110% of the performance, expect it to cost $1,725.
Spunjji - Wednesday, June 1, 2016 - link
There's a small fault in your logic, which is that if they priced it like Intel are here they would sell as few of them as Intel clearly expect to, and thus struggle to make the market share gains that they badly need.I'd expect a competitive product to cost something more like $1000 (at which price they would still be making PHENOMENAL margins) and force a price-drop from Intel. They're not going to give anything away for free, but they absolutely stand to benefit from being less obscenely liberal with their margins than Intel.
This is assuming they execute on time and as promised, which is, well, not very AMD of late.
cswor - Wednesday, June 8, 2016 - link
I agree. In their underdog position, they need to undercut and can still probably make a nice profit on a chip priced to sell larger volumes, assuming it performs and they can manufacture it.Azix - Tuesday, May 31, 2016 - link
AMD might not have the luxury of not going for the jugular. If the yields aren't great maybe their prices will be that high. They won't gain market share/mind share with high prices though.just4U - Tuesday, May 31, 2016 - link
They won't be that high. AMD has only been able to price their higher end consumer processor at intel pricing "once" (to my knowledge) and it didn't stay there long.nandnandnand - Tuesday, May 31, 2016 - link
How do we know that Zen is that close to Broadwell in IPC (and Skylake, since there is very little difference)? I'd love for it to be true, but AMD's Zen 8 cores need to solidly beat Intel's quad cores and do almost as well in single threaded performance.retrospooty - Tuesday, May 31, 2016 - link
" Zen is supposed to be really, really close to Broadwell in IPC"- What has AMD done in the past decade that makes you believe that? I will believe it when its released and retail units (not engineering samples) are independently tested. Until then I don't believe anything AMD says.
Drumsticks - Tuesday, May 31, 2016 - link
I'm not about to sing the praises of AMD completely yet, but I think there's reason to believe they're more focused than they've been in the last ten years. On top of that, Jim Keller was good way back when, he's proved he still has great ideas now with Apple, so there's hope that Zen could really impress. They still have to execute (something we know isn't a given for AMD) but we'll know all in a few months time.If the rumors were true about Vega in October (I doubt they are), they could have a pretty nice high publicity 1-2 punch. It's unlikely Vega will show up then, but I'd be pretty happy if it did.
retrospooty - Tuesday, May 31, 2016 - link
I hear you, and I have heard that too... But all the same, AMD's PR is always far more active than their engineering teams leading up to launch. If it comes out and is as fast as they seems o think it will be and doesn't have any major heat or power issues (that cause the need to clock it lower than expected) it may be good... All the same, its best to wait until retail chips are released, prices set and units reviewed to decide.michael2k - Tuesday, May 31, 2016 - link
I am enthusiastic too, but if Zen really is that powerful I cannot imagine it selling at 30% of Intel prices. The more powerful the part, the higher the price will be, up to 90% of Intel's prices for similar performance.