MultiCore Enhancement: The Debate About Free MHz
by Ian Cutress on August 29, 2012 5:45 PM EST- Posted in
- Motherboards
- CPUs
If you have been keeping up to date with any of the AnandTech motherboard reviews lately, there has been one topic that has been hot on my lips, and it is called ‘MultiCore Enhancement’. As an exercise in explanation and opinion, we would like to know your thoughts on this, and how it would affect you as a user.
To start, let me describe what we are talking about. On the latest line of Intel CPUs, we have multiple cores all willing to provide computational throughput. The CPU itself has a listed stock speed, and a thermal window to ensure stable operation. At the stock speed, the CPU does not hit the thermal window, so Intel assign higher speeds depending on how much computational power is needed, and this is adjusted to fit inside the power requirements. Thus when a user requires only one CPU core, the CPU can be allocated the maximum turbo speed – when more cores are requested, the speed of the CPU drops until all cores are in use. This is what Intel designates the ‘Turbo Boost’ for the CPU.
In the case of the latest Ivy Bridge CPU, the i7-3770K, this CPU has a nominal speed of 3.5 GHz. However, the turbo boost is set such that in single threaded mode, the CPU can run at 3.9 GHz by adjusting the multiplier to 39x. As more cores are loaded, the CPU reduces the multiplier down, until all four cores are in use and the processor is running at 3.7 GHz, still 200 MHz above the rated speed on the box. This also applies to other processors:
| CPU Turbo Bins | |||||
|
i7-3770K (4C / 8T) |
i7-3570K (4C / 4T) |
i7-2600K (4C / 8T) |
i7-3960X (6C / 12T) |
i7-3820 (4C / 8T) |
|
| Rated Speed | 3.5 GHz | 3.4 GHz | 3.4 GHz | 3.3 GHz | 3.6 GHz |
| 1 Core | 3.9 GHz | 3.8 GHz | 3.8 GHz | 3.9 GHz | 3.9 GHz |
| 2 Core | 3.9 GHz | 3.8 GHz | 3.7 GHz | 3.9 GHz | 3.8 GHz |
| 3 Core | 3.8 GHz | 3.7 GHz | 3.6 GHz | 3.8 GHz | 3.7 GHz |
| 4 Core | 3.7 GHz | 3.6 GHz | 3.5 GHz | 3.8 GHz | 3.7 GHz |
| 5 Core | - | - | - | 3.7 GHz | - |
| 6 Core | - | - | - | 3.6 GHz | - |
However this technology is not defined by the processor itself. The act of telling the processor to run at a certain speed is set by the motherboard, not the processor. So as part of the deal with Intel, motherboard manufacturers’ code in the BIOS the algorithm to make the CPU switch speeds as required. This algorithm can be aggressive, such that turbo boosts are held for a short time when CPU loading goes from low to high, or instant when CPU power is needed or not needed. This algorithm and switching speed can determine how well a motherboard performs in CPU benchmarks.
This is all well and good when every manufacturer adheres to this specification. But a new ‘feature’ has made its way onto our motherboards. Since X79, ASUS has been implementing a feature they call ‘MultiCore Enhancement’ whenever XMP has been set. Gigabyte has implemented this since their Z77 suite but as of yet leave it un-named, and ASRock are going to start using ‘MultiCore Acceleration’ with their Z77 OC Formula. EVGA also has something in the pipeline for their Z77 boards. This feature, put simply, gives the CPU some extra speed.
With these motherboards, usually when XMP is enabled, the CPU is told to use the top turbo boost setting under all loads. That means a CPU like the i7-3770K has only two speeds – 3.9 GHz while under CPU load, and 1.2 GHz at idle. For motherboards that implement this feature, they get a significant boost in their CPU benchmark scores. As a result, the user who runs their processor at stock also gets up to 300 MHz more speed during multithreaded loading.
Technically, this is an overclock. Typically we are told that overclocking a system is liable to void the warranty on both the processor and the motherboard. With the case of the processor, typically what Intel put on the shelves is a safe speed – they are not pushing any competition to the limits, so these processors have breathing room and this ‘overclock’ should not harm longevity. Nevertheless, Intel is usually very willing to replace processors (if I extrapolate the stories of returns I have heard). With motherboards, they are designed to hold the top turbo bin at single core loads, so full threaded load should not be much of an issue. Given that it is the motherboard manufacturers themselves that apply this, it would be reasonable that RMAs would be honored.
There has been a precedent with this in the past – when Turbo Boost was not part of the processor paradigm, motherboard manufacturers used to play around with the CPU FSB speed before it was passed through the multiplier. So instead of 100.0 MHz on the FSB, we used to get 100.3 MHz, 100.8 MHz, 101.3 MHz, and even a case of 102.1 MHz I believe. So essentially, a free 2.1% overclock if you ran the processor at stock speeds.
Given all this, I recently tested one motherboard that pushed the boundaries beyond the ‘normal’ MultiCore Enhancement. The Gigabyte G1.Sniper 3, by default, gave the i7-3770K a 4.0 GHz turbo mode at any speed. As a result, it took top spot in all our benchmark settings. The G1.Sniper 3 is a high end product, so producing the jump was not much extra work for the product itself. However, it does open up a variety of questions.
- How many users run processors (K or non-K) at stock?
- How many will notice the difference in speed?
- Will they worry that technically it is an overclock?
- Will a manufacturer go that one step further, to 4.1 GHz, or 4.2 GHz? What is a safe limit?
Here are the results from one of my benchmark tests. Here is 3DPM, a memory agnostic benchmark, using the multi-threaded version:
Here we see that the boards with MCE all come top. More cores means more points, and more MHz is king. Boards without MCE have to have an aggressive turbo switching algorithm to stay close, or fall behind up to 10% away from those without MCE.
I would like to cite some scenarios involving individuals and their computers in order to draw some conclusions.
- Person 1 uses his machine for gaming. While an active gamer, his budget is low and does not know how to adjust the BIOS, but his system plays his games well enough not to overclock.
- Person 2 is an enthusiast with a high budget. His system uses the best components, and he is always striving for top speed through overclocking.
- Person 3 uses their pre-built machine for work and email, sometimes watching movies or video websites. They have no need for overclocking.
- Person 4 has a low power HTPC, and is focused on keeping his footprint green. They buy a low powered CPU, and use it to watch videos. The system is not underclocked, but when under load, the CPU will implement the full turbo mode.
Deductive reasoning tells us that Persons 1 + 3 will benefit slightly from MultiCore Enhancement, however the gamer moreso than the worker. Person 2 overclocks, and thus MCE does not affect them. Person 4 is more like a victim of MCE – without going into the BIOS they are unnecessarily using more energy than needs be.
Several companies have approached me and ask why I test motherboards with MCE enabled. My response is that I test the ‘out of the box’ performance for the majority of users, such as Person 1, or system builders making machines for Person 3. If I pre-overclocked the normal ATX boards, while that would help Person 2 in their decision, I would have to do it as well for Person 4 in order to keep the comparisons between ATX and mITX relevant. Keeping everything at default on the latest BIOS is a steady baseline between these scenarios – if a motherboard manufacturer wants to be aggressive and enable MCE (or MCE-plus), then that is up to them. But as a result of MCE, some companies who have not enabled it are being left behind in terms of stock CPU performance.
The point of this pipeline post is to ask our readers what they think of MultiCore Enhancement. Do you like it? Does it matter to you? Should it become the standard, or should companies offer different SKUs with and without MCE? If two motherboards from different companies are all equal on price and features but differ by MCE, would you go for MCE? Would you worry about longevity? Please let us know in the comments.
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law99 - Wednesday, September 5, 2012 - link
I'm defending your decision and your point. Stock is the only fair way to do it... and for you that should be stock out the box.The manufacturer has to live with the decision it made, not the reviewer. You shouldn't have to compensate for the way they want average Joe to perceive their product.
And I probably should clear up what I meant above; a lower clocked processor of the same family will complete the task slower than the performance model. Meaning that as long as the idle consumption on the higher performance part is the same or similar, overall consumption can murky the waters with a performance part consuming less over all due to finishing faster.
Why should that matter for mobo designers though? Like you say, it can inflate certain performance figures, but as stock options should create an entirely differnet level playing field. One where those ratings become more interesting.
The only people I can really see having a say in the end are AMD and Intel through compliancy. In the meantime I'd commend you for keeping things level the only way that is fair, with the least effort required by me to match it.
law99 - Wednesday, September 5, 2012 - link
I may need a little more elaboration on your point here but, time and time again, we see that low power alternatives consume less power over longer periods, thereby consuming more than their high powered counterparts.If this is true, we can take it to mean that if anything power vs performance graphs just got more interesting.
The only time I can see that this may be of negative impact to such a metric would be if video playback is involved and the mobo is constantly jumping between a low base and inflated top clock.
In which case, as these mobos and their respective makers purposely implemented these features, if anything, the results will further help you to seperate the wheet from the chaff at a low power point.
jtd871 - Wednesday, August 29, 2012 - link
Ian, thanks for asking for the feedback.I do wonder about the effect on the effective lifespan of the CPU under MCE vs. a "stock settings" approach. It may be too early to tell how robust the various flavors of Ivy Bridge are.
I'm also of the school that thinks that overclocking for overclocking's sake is a bit of a waste, since most of the high-end processors are ridiculously powerful for the vast majority of consumers' needs at their stock performance, and that one downside of enabling MCE as a default is that inexperienced users may push beyond the safe limits of stock cooling solutions, and wonder why they can't get the processor to run at the higher clocks.
I think that as long as the vendors educate the users about the presence of MCE on their machine, discusses the advantages, disadvantages and provide simple and effective software to enable/disable it through the OS that won't let you brick your machine, then the user can make the choice of whether to disable it or not.
j
IanCutress - Thursday, August 30, 2012 - link
Making MCE go beyond cooling will depend if manufacturers want to push the limits of MCE-plus, i.e. go one turbo bin above stock settings, or maybe even two or three. I have a feeling that manufacturers test internally with the Intel stock cooler to ensure compatibility, but in the future you may see a board bundled with a CPU cooler for this very purpose. Perhaps.Don't forget that once a user tries to overclock, whether a board has MCE or not is no longer an issue. If the user is overclocking, then it's up to the user to provide sufficient cooling. I'm a competitive overclocker, so I enjoy overclocking for overclocking sake - my gaming PC is overclocked and has an All-In-One liquid cooler, but my home system is at stock and MCE makes me run just a tad faster in unzipping files, encoding video et al.
Ian
Rjak - Wednesday, August 29, 2012 - link
The MSI Z77A GD65 does have MCE, it's just disabled by default.In the BIOS it's called "Enhanced Turbo", and I have it enabled - it's the only overclocking feature I currently have enabled on that system (the RAM I have at 2133, but it's rated for that).
A faster computer is nice, but for what I'm doing the overall system performance isn't improved enough to justify an overclock that will add 10-15 degrees or so.
frogger4 - Thursday, August 30, 2012 - link
[long time reader, first time commenting]Given that MCE is a feature in the motherboards, and given that the purpose of a motherboard review is to consider its features (especially against boards lacking a feature), I think it makes sense to do the reviews with MCE enabled (or however the board comes stock).
Although it doesn't affect me (990X @ 4.3GHz) of course, it seems like a very sensible thing for the motherboard manufactures to do. It is literally free performance - no reason to complain there. And, since the reviews take into consideration power use, the extra power consumption will not go without proper consideration.
Streetwind - Thursday, August 30, 2012 - link
I think this development is largely a result of the increasing difficulty mainboard manufacturers face when it comes to differentiating their products.Back in the day, chipsets were a big deal that housed many important system components, and they were manufactured by several third party companies. Nowadays, Intel supplies the chipsets more or less exclusively, and the CPUs cannibalize them for functionality more and more with every generation. What kind of motherboard you use has never been so completely and utterly unimportant for your computer's performance as it is today.
Look at ASUS: The entry-level $130 P8Z77-M mATX, the top of the line $280 P8Z77-V DELUXE ATX, and the specialty-built $200 P8Z77-I Deluxe mini-ITX boards. They have the exact same chipset, the exact same feature set, they even literally have the same firmware. Think 10 years back - if someone had told you that you'd have the option to clock a CPU to the limit of your cooling solution and configure the most obscure memory subtimings on a company's cheapest possible offering on the market, you'd have laughed in disbelief. The only thing the more expensive boards offer is more auxillary components, like double WLAN antennas and dozens of extra USB 3.0 and SATA ports that 95% of all people will never touch, and fancy-looking passive coolers that are even more superfluous.
Add to that the rapid expansion of the internet and the ever-growing importance of independent reviews in the eyes of the customer. The manufacturers want and must be ahead in the graphs, even if it's by a metric that doesn't matter. Fewer people will want to buy a product that is at the bottom of the chart, and explaining that "we are simply keeping within Intel's specifications" is irrelevant. Few enough people even read the text accompanying the charts, and even less truly understand and remember it. And likewise, tons of superficial reviews don't even mention these details. I mean, that's why we come to Anandtech, no? You don't get quality reviews and a quality readerbase at once just anywhere, after all! ;)
Ironically, those people that are liable to read reviews are those that benefit least from MCE - namely those people who will go and tweak their settings anyway, even if they are not true enthusiasts. As such, I would consider this feature merely marketing shenanigans and customer misdirection... were it not for the fact that having the choice whether to stagger your turbo bins or keep them all at the same level is in fact a choice that I like having.
Malih - Thursday, August 30, 2012 - link
Probably Intel should have a standard on how this MultiCore Enhancement should be done, instead of letting each manufacturers doing it differently, especially on ITX systems, they should be turned off by default, but with the ability to toggle it on the EFI/BIOS.IanCutress - Thursday, August 30, 2012 - link
Unfortunately, Intel can specify what they like. They already specify the Turbo bins. If the motherboard manufacturer wants to produce out of spec, then that's up to them and they are free to do it.Ian
Mr Perfect - Thursday, August 30, 2012 - link
It makes me wonder if Intel will look into moving the turbo control CPU-side, much like how they have multipliers defined in the CPU now.