The Intel Broadwell-E Review: Core i7-6950X, i7-6900K, i7-6850K and i7-6800K Testedby Ian Cutress on May 31, 2016 2:01 AM EST
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Turbo Boost Max 3.0 (TBM3), aka Turbo Boost Max or Turbo Boost 3.0
When Intel released the enterprise focused Broadwell-EP Xeon CPUs, there were a few features added to the platform over the previous Haswell-EP generation. One of these has come through to the consumer parts, though in a slightly different form.
For Broadwell-EP, one of the new features was the ability to have each core adjust the frequency independently depending on AVX or non-AVX workloads. Previously when an AVX load was detected, all the cores would reduce in frequency, but beginning with BDW-EP now they act separately. Intel has taken this enterprise feature and expanded it a little into a feature they're calling ‘Turbo Boost Max 3.0’.
Turbo Boost 2.0 is what Intel calls its maximum Turbo or ‘peak’ frequency. So in the case of the i7-6950X, the base frequency is 3.0 GHz and the Turbo Boost 2.0 frequency is 3.5 GHz. The CPU will use that frequency when light workloads are in play and decrease the frequency of the cores as the load increases in order to keep the power consumption more consistent. Turbo Boost 2.0 frequencies are advertised alongside the CPU on the box - TBM3 will be slightly different and not advertised.
TBM3, in a nutshell, will boost the frequency of a single CPU core when a single-threaded program is being used.
It requires a driver, similar to Skylake’s Speed Shift feature (which is not in Broadwell-E), which should be distributed in new X99 motherboard driver packages, but will also be rolled out in Windows 10 in due course. It also comes with a user interface, which might make it easier to explain:
Each of the cores in the processor can be individually accessed by the OS with the new driver, and the cores will be rated based on their performance and efficiency as they come out of Intel. In the image above, Core 9 is rated the best, with Core 0 at the bottom. This means that for TBM3, the driver will primarily use Core 9.
When enabled, TBM3 will activate in two modes: either the foreground application, or from a priority list. For the foreground selection, when the software detects a single threaded workload in play, it will attempt to pin the software to the best core (similar to changing the affinity in task manager to one core), and then boost the frequency. In priority mode, the application will look for any application on the left-hand panel (which has to be added manually). If an application with higher priority is present, then the software will unpin the current software and take the higher priority one and pin that instead.
When pinned, the software will boost the frequency of that core only. The only question now is how much is the boost, and what is the effect on performance? Unfortunately, both of those questions have bad answers.
Intel refuses to state the effect of TBM3, saying that ‘each CPU is different and could boost by different amounts’. Now, you might think that makes sense. However…
Turbo Boost Max 3.0 has to be supported by the motherboard manufacturer in the BIOS. The TBM3 settings have to be set in the BIOS, which means that the usefulness of such a feature is actually down to the motherboard manufacturers. But they know how to do it right, right? Well, here’s where it can get worse.
On the MSI motherboard we used for most of our testing, Turbo Boost Max 3.0 was disabled by default in the BIOS. We asked about this, and they said it was a conscious decision made by management a couple of weeks prior. This makes TBM3 useless for most users who never even touch the BIOS. That sounds good, right?
Well, the BIOS also sets how much the CPU can boost by. So ultimately it doesn’t matter how much the CPU might like to boost in frequency, the system will only boost by the amount it says so in the BIOS, which is set by the motherboard manufacturer. In the case of the MSI BIOS, it was set to ‘Auto’. In my case, ‘Auto’ meant a boost of zero, despite the MSI BIOS ‘suggesting’ 4000 MHz. I had to manually set Core 9 to a 40x multiplier. Then it worked.
All in all, TBM3 was only enabled after I changed two settings and specifically setting the correct core in the BIOS. For me, this isn’t a global feature if that is the case. That’s not to mention how Multi-Core Turbo also comes into the mix, which still works with Turbo Boost 2.0 speeds by default. Based on what we've seen, it would seem at this time that TBM3 isn’t being readily embraced at this time.
It should be noted that we also had one of the new ASUS motherboards in for testing, however time was too limited before leaving for Computex to verify if this is the case on the ASUS motherboard as well. ASUS has told me that they have/will have a software package that enables TBM3 to be applied to multiple cores at once, whereas the Intel software will only accelerate a single program. It should be interesting to test.
The Reviewers Problem With Turbo Boost Max 3.0
In the options menu for TBM3, there are two primary options to take note of. The first is the utilization threshold, which is the % at which the software will take control of the single threaded application and pin it to a core. By default, this is set at 90%.
The other option is where a dilemma will be faced. It is the evaluation interval, or the period of time between checks that the software makes in order to accelerate a program. The version of the software we had started with a value of 10 seconds. That means if the software package starts one second or nine seconds into a benchmark run, it can affect the score. The answer here would be to make the evaluation interval very small, but the software only has a one-second resolution. So for benchmarks that run for only a few seconds (anyone benchmarking wPrime or SuperPi, for example), might either fail to be accelerated if the evaluation window is set at default, or only slightly when set at one second.
As you can imagine, if a reviewer does not know if TBM3 is enabled or not, there may be some odd benchmark results that seem different to what you might expect. It should be noted that because of the BIOS issue and the potential for motherboard manufacturers to do something different with every product, we ran our benchmarks with TBM3 disabled, and readers should check to see if reviewers specify how TBM3 is being used when data is published.
Package Differences: It’s Thin
When the Skylake mainstream platform was launched, it was noted that the processor packages and substrates were thinner compared to the previous generation. It would appear that Intel is using the same packaging technology for Broadwell-E as well.
On the left is the Haswell-E based Core i7-5960X, and on the right is the Broadwell-E based Core i7-6950X. Both of these platforms use a FIVR, the Fully Integrated Voltage Regulator, which Intel equipped on this microarchitecture in order to increase power efficiency. Usually the presence of the FIVR would require additional layers for power management in the package, but it would seem that Intel has been optimizing this to a certain extent. Each individual layer is certainly thinner, but it is likely that Intel has also reduced the number of layers, though my eyes cannot discern the resolution needed to see exactly how many are in each CPU (and I don’t have a microscope on hand to test).
A couple of questions will crop up from readers regarding the thinner package. Firstly, on the potential for bending the package, especially in regards to a minor story on Skylake where a couple of CPUs were found to have bent when under extreme cooler force. As far as Intel is aware, Broadwell-E should not have a problem for a number of reasons, but mostly related to the dual latch socket design and socket cooler implementation. Intel’s HEDT platforms, from Sandy Bridge-E on, have been rated as requiring 30-40% more pressure per square inch then the mainstream platforms. As a result the sockets have been designed with this in mind, ensuring the pressure of the latch and cooler stays on the heatspreader.
The other question that would come to my mind is the heatspreader itself. Intel has stated that they are not doing anything new with regards to the thermal interface material here compared to previous designs, and it is clear that the heatspreader itself is taller to compensate for the z-height difference in the processor PCB.
If we compare the ‘wing’ arrangement between the Haswell-E and Broadwell-E processors, Intel has made the layout somewhat more robust by adding more contact area between the heatspreader and the PCB, especially in the corners and sides. One would assume this is to aid the thinner PCB, although without proper stress testing tools I can’t verify that claim.
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SAAB340 - Wednesday, June 1, 2016 - linkIf 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 - linkI'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 - linkIt 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 - linkWell 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 view
Eden-K121D - Tuesday, May 31, 2016 - linkPeople on Haswell are well and good until something extraordinary comes out of intel/AMD
Michael Bay - Wednesday, June 1, 2016 - linkWhen 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 - linkExactly. 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 - linkTo 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 - linkIndeed! 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.