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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SAAB340 - Wednesday, June 1, 2016 - link
If possible, can you have a look in to RAM overclocking as well. I believe the memory controller in Haswell-E isn't particularly great. The one in Skylake is way better. I wonder if Broadwell-E has improved there?I know RAM speeds in general don't make that much difference but in certain applications it does.
StevoLincolnite - Tuesday, May 31, 2016 - link
I'm still happily cruising with a 3930K. The 5930K was the twice the price of the CPU alone for what I paid for my 3930K, but it certainly doesn't offer twice the performance and the 6850K looks to be more expensive again.My 3930K still has a few years of life left in it, hopefully AMD can bring Intel's prices downward.
Witek - Thursday, June 16, 2016 - link
@SteveoLincolite - agreed, I am still on 3930K for more than 3 years now, and I would be happy to switch to something faster, but 6800K is essentially same speed, only faster in specialized workloads, and probably 2 time more costly. Going from 6 to 8 cores, only gives me 30% boost, for almost 4-5 times the prices. The 10 core one is a joke.3930K (and it overclocks easily too - 3.2GHz -> 4.2GHz with water cooling non stop in my setop), is still the best value out there probably.
prisonerX - Tuesday, May 31, 2016 - link
It cracks me up that people pay say $300 for a mainstream i7 which is 65% graphics which they don't use, but employ that same silicon for a few more cores and the price is $1000+.People belittle AMD for not having the fastest silicon and then touch their toes price wise for whatever scraps Intel throws them. Particularly funny since mainstream processors were 5% slower in the last generation. It's like people are suffering Stockholm syndrome or something.
Alexey291 - Tuesday, May 31, 2016 - link
Well it's little wonder that the cpu market is slowing down since there are no actual products worth buying from a mainstream purchasers' point of viewEden-K121D - Tuesday, May 31, 2016 - link
People on Haswell are well and good until something extraordinary comes out of intel/AMDMichael Bay - Wednesday, June 1, 2016 - link
When the most exciting thing about a platform refresh is a goddamn usb3.something type-whatever port, writing is on the wall.beginner99 - Tuesday, May 31, 2016 - link
Exactly. It's not slowing down because of smartphones or tablets but because 5% performance increases takes 10 years for the average user to be worth an upgrade.Ratman6161 - Tuesday, May 31, 2016 - link
To take that one step further, for the average user it isn't even 5%. They aren't doing anything with the machine that isn't entirely adequate with what they have. I don't consider myself to be the average user by any means, but my i7-2600K system i built in the spring of 2011 is still more than fast enough for anything I do let alone spend money on a 6700K let alone any of these.mapesdhs - Thursday, June 9, 2016 - link
Indeed! This week I need to put a system together for handling SD video. I have at my disposal a whole range of SB/SB-E i7s, but they're overkill, so I'm going to reuse the parts from my brother's old PC instead, a P55 with an i7 870 which, at 4.2GHz, is still rather good (people forget it was a particularly low latency platform for its time, with boards that really did push what features one could include, some good innovation with slot spacing and other things). My own general tasks system, a 5GHz 2700K, I can't see becoming obsolete for a long time, it handles everything with ease (scores 880 for CB R15).And this is the key problem: it's the very tasks that would benefit the most from real performance and feature improvements where newer products have helped the least, baring in mind the upgrade costs involved and the lack of feature enhancements over the years (how long was it until Intel finally added native USB3 to the top-end chipset?). Given the cost, the gains of the latest top-end CPUs over what was available in 2011 just aren't worth it, which perhaps explains why I see comments even from X58 6-core owners saying they'll stick with their setups for now). Meanwhile, for anyone on a budget who doesn't want to consider 2nd-hand items, it's hard to ignore the value of AMD's current 4c and 6c offerings (heck, the PC I built for my gf is an old Ph2 X4 965 and it's more than adequate), given that really, for response and feel of a normal PC, having an SSD is more important than having the higher IPC of a costly Skylake vs. an FX 6300 or something.
I was shocked at the launch price of the 6700K, and I didn't think Intel would make the same mistake again, but they have. One of the main things I do is offer free upgrade advice for prosumers on a limited budget (typically self-employed artists); atm, the 6950X is so expensive that I'd recommend a 2-socket XEON setup instead without hesitation. 3 years ago this wasn't the case, back then there was a solid rationale for (example) an AE user on a limited budget to build an oc'd 3930K. Today though, what Intel is doing will only help reduce the enthusiast market even further, and I was told by a high street shop owner that the top-end items are the ones which provide the best margins (he said his store couldn't survive on the mainstream level sales). There will be long term self-reinforcing consequences if Intel doesn't change direction. Perhaps Zen will achieve that; certainly many seem to hope it will.