Intel Core i7-3960X Review Page: 1

Intel Core i7-3960X Review


Anyone who has a passing interest in gaming knows that this years game version comes with next years date upon it. Either that or EA Sports are capable of coding in the future. But with Intel, if it's the year 2011, then it must be time to take a look at the LGA2011 we've all be waiting for. Even if the 2011 connection is merely coincidental.

Intel always work on a Tick Tock system, wherein the Tock is a major hardware revision, and the Tick is a refinement of that, normally a die shrink. Today we're looking at the Tick in the cycle, but changes are such it doesn't easily fit into either category. Sit tight, this will get technical.

To bring you swiftly up to speed, in November 2007 Intel released the first 45nm architecture, the Tick, which was the Core 2 revision. A year later we saw a huge shift in processor capabilities with the Tock of Nehalem, the original 45nm Core-i7s and also the LGA1156 i7-870, i5-760 etc. This was refined with the Tick of the Westmere die-shrink down to 32nm which we saw as both the LGA1366 i7-970, i7-980 and i7-990. The next Tock we saw was Sandy Bridge which introduced the LGA1155 socket and 32nm i7-2600Ks and the like.

That is now adjusted with a the Tick we're looking at today which, on previous form, should be a die-shrink, but it's retaining the 32nm process. It isn't retaining the LGA1155 socket either, rather introducing the LGA2011 socket. It's not even a successor to the current i7-2600K's. What it actually is is moving the high end X58 Hex-Core i7s from the Westmere range (990X etc) onto the Sandy Bridge line, here labelled the Sandy Bridge E and adding Quad Channel memory support.

Every new socket release comes with a new chipset, and the LGA2011 has the X79 chipset to keep it company, with USB 2.0 only (USB 3.0 comes via the usual NEC Chip), two SATA 6Gbp/s sockets on the chipset, and support for PCI Express 3.0. Because of this we're testing the Core i7-3860X CPU on the latest Intel DX79SI motherboard so we've got a lot to cover. 3.3GHz of Hexcore hyper-threaded goodness coming right up.

We'll try and keep it all as clear as possible. Let's start with the CPU.

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Intel Core i7-3960X Review

Intel Core i7-3960X

The diagram of the CPU die shows the deceptively simple layout of the various components. We're sure we can't be the only people who've noticed the 8 Core spaces only filled up by 6 Cores. The ones we do have each support a single Hyper-Thread, giving us 12 threads on this particular CPU. The cores have 32KB of instruction cache and 32KB L1 cache. Level 2 cache is provided by 256KB of shared instruction and L2 cache, whilst 15MB of L3 cache is shared between the cores, with up to 2.5MB available per core.

The Memory Controller is retained on the CPU, continuing the trend that Intel have had for a few processors now. Equally the I/O is also integrated. The merging of the Southbridge onto the CPU is expected in the next revision.

The diagram on the right shows that the new 2011 processors support Quad Channel RAM, for those of you with a unquenchable thirst for memory. It does however state the PCI Express is 2.0, whereas it's up to 40 lanes of PCI Express 3.0, as indicated in all the other literature, and the physical board itself. See the slide below for further clarification, or muddying depending on your outlook.

Intel DX79SI and Core i7-3960X Review     Intel DX79SI and Core i7-3960X Review  

There are a lot of tweaks behind the scenes that to you and me, the average end-user, aren't worth going over too much. We're fairly certain that if you're the kind of person who needs to know that the i7-3960X supports "46 bits of physical address space" and has "static lane numbering reversal and polarity inversion support" then you'll be more willing to delve into the finer points of the documentation.

For us though the important things are neatly summed up in the following slides. 6 Cores hyperthreaded cores giving us 12 threads to play with is the same as all the high-end X58 processors. The really big adjustment for our fun and games is the move from the initially expensive and under-performing Triple Channel RAM of the X58 boards into the world of Quad Channel memory. Thankfully because the LGA2011 is based upon the already successful LGA1155 dual-channel RAM, it's a simple upgrade as the memory is already available at the required voltages.

This left-hand slide also indicates that the combination of the Core i7-3960X and X79 chipset enable the support for PCI Express 3.0, without stating which of the two actually provides it. Given that you can't have one without the other it's not hugely important. What matters is that it supports PCIe 3.0.

We will get into the overclocking side of things more when we take a look at the BIOS on the DX79SI motherboard, but for now it's worth noting some very cool changes. Rather than the simple but limited overclocking available on the SandyBridge, or the complex but open-ended overclocking we saw from the X58 series, the LGA2011 has a nice middle ground. The 'automatic' overclocking actually takes into account the uprated voltages and TDP limits needed to stably sustain an overclock. Also the memory isn't limited to the rather coarse dividers we saw in Sandy Bridge, but there is a 1.25 'gear' option that allows for 1666MHz or 2000MHz. Good for getting a little extra performance without crossing the yawning chasm between 1866MHz and 2133MHz.

Intel DX79SI and Core i7-3960X Review     Intel DX79SI and Core i7-3960X Review  

Finally we see where Sandy Bridge E, LGA2011, fits in the Intel Roadmap. We can also see the potential performance improvements of the combination between the Core i7-3960X and the Intel DX79SI motherboard and the old X58 i7's. Testing the performance is obviously what we're here for, but before then let's grab a look at the motherboard today's fun is being held on.

Intel DX79SI and Core i7-3960X Review     Intel DX79SI and Core i7-3960X Review

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Intel Core i7-3960X Review

Intel DX79SI Motherboard

Intel motherboards have always had an air of simplicity to their packaging. Largely because I think they're aware that few people actually choose one as the heart of their system, but equally because they're Intel, and don't need to advertise the fact. In the world where brand names are the most vital factor in customer loyalty, Intel are the Coke of the hardware world.

Despite that we do like the black and blue colour scheme, as well as that impressive skull. Who doesn't like skulls?

Intel Core i7-3960X Review     Intel Core i7-3960X Review

Looking at the board as it arrives out of the box, a couple of things grab us straight away. Firstly the addition of four extra RAM slots to the left of the CPU mean that the heatsink we've all come to love no longer exists. Yet removing the cooling that does remain shows that very little of it is actually important. The central one above the top PCI-e slot is purely for show, and the chipset heat-sink isn't exactly on top of anything large.

The DIMM sockets support anything from Dual Channel, Triple Channel and our new friend Quad Channel, as well as RAM up to DDR3 2400.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

The CPU socket is where we find our second change. Rather than the single-lever design we've all come to know and love, the LGA2011 has two levers applying pressure to the CPU. Although we've never heard of any issues arising from the single lever design, a more uniform retaining mechanism can only be a good thing.

The DX79SI is almost the antithesis of many motherboards we've seen. How often do you find yourself staring blankly at an array of pins and things without knowing what all of them do? Intel have removed the need to study the manual deeply by labelling absolutely everything. If it exists on the board, it's got a label. That does render my job of explaining it all rather moot. However, across the bottom of the board we have the various headers, including as many USB 2.0 headers as we've ever seen. The 7 segment POST display is in an easy to see location, unless you've got Triple GPU of course. The three PCIe sockets are all x16, although the bottom one is electrically x8 and the middle is x8 switchable.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

Storage is supplied by two SATA 6Gbp/s ports and four SATA II ports. The SATA II support RAID 0,1, 5 and 10 should you require them. These are provided by the chipset itself.

At the back we have dual GigaLAN, six USB 2.0 ports, two USB 3.0 ports, a FireWire and the jacks for the RealTek ALC892 audio.

Intel Core i7-3960X Review     Intel Core i7-3960X Review

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Intel Core i7-3960X Review

Intel DX79SI In Detail

With the addition of the four extra DIMM sockets the power has moved to entirely DPM, greatly reducing the footprint of the power phases.

Intel Core i7-3960X Review     Intel Core i7-3960X Review

Demonstrating how much of the controllers have moved to the CPU, the middle heatsink rests solely upon a couple of solid state capacitors.

Intel Core i7-3960X Review     Intel Core i7-3960X Review 

CPU power is thankfully still provided by a single 8 pin 12V connector, ensuring that upgrading to the X79 doesn't require an entirely new system.

There are so many headers that it's nearly impossible to find a bit of room across the bottom of the DX79SI that doesn't contain some expansion headers or whatever. A nice touch is the POST code display being right next to the power buttons for easy reading.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

Beneath that large skull motif cooler we have two main chips. The Winbond reports the voltages and temperatures and the like. On the right we have the heart of the beast, the X79 itself. It looks just like the old Pentiums. How far we've come.

Intel Core i7-3960X Review     Intel Core i7-3960X Review

This little button on the left has some clever trickery behind it. It allows the system to boot directly into the BIOS using default settings, without actually losing the configuration you've done yourself. How amazing this is cannot be understated. How often have we overclocked, then the system hangs or wont POST and you have to start again with a CMOS clear and waste ages going back through the various bits and bobs necessary to obtain large overclocks. With this you just press it and you're back up and running. It's wonderful, and really should be a feature on every motherboard made from now on, it makes the job that much easier. Indeed we think it's of such importance that Intel need to make its inclusion part of the contract that allows people to base their boards upon the X79 chipset.

Intel Core i7-3960X Review     Intel Core i7-3960X Review

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Intel Core i7-3960X Review


We'll just be skimming across the BIOS for the Intel i7-3960X on the DX79SI as the processor bits are largely overclocking based. Despite the main base clock being 100MHz, as it was locked to on the Sandy Bridge line, there are some multipliers in play no so that you have a broader array of ways to get the CPU speed you desire. So here we have 1.25 multiplier for 125MHz BCLK and 1.67 multi for 167MHz. This frees you from solely utilising CPU multipliers to obtain your overclock.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

Similar to the overclocking options available on the LGA1155, the LGA2011 allows us to adjust the turbo multiplier based on the amount of cores being utilised, as well as altering the maximum Amps and Watts that the CPU is capable of drawing upon.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

Memory multipliers are still in play, although the combination of the Host Clock Multiplier and the Memory Multiplier gives us a larger choice of RAM speeds. Instead of just having 1333MHz, 1600MHz, 1866MHz and 2133MHz, which are all fairly large leaps beyond the abilities of most RAM kits, you can also have 1666MHz and 2000MHz. It's much easier to get a 1866MHz kit to run at 2000MHz than 2133MHz, or you can tighten the timings of a 2133MHz kit without overly restricting the frequency of your RAM.

In short, there are a lot of extra options available on the Sandy Bridge E than existed on the plain Sandy Bridge.

Intel Core i7-3960X Review

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Intel Core i7-3960X Review

Test Setup

Being a refinement of already existing technology we're able to use a large amount of our standard test setup for our review of the Intel Core i7-3960X. One of the biggest changes, besides the obvious board/CPU one, is the move to Quad Channel RAM. G.Skill have recently been included into the official Intel XMP partner list and provided us with a set of their RipjawsZ for todays testing. 16GB @ 2133 9-11-10-28. We're pretty certain this makes it the fastest kit around with 4GB density sticks.

Intel Core i7-3960X Review     Intel Core i7-3960X Review  

Intel Core i7-3960X Review     Intel Core i7-3960X Review

As for the rest of our test setup it's similar to our normal one :

Intel Core i7-3960X
Intel DX79SI Motherboard
nVidia GTX570
ForceWare 285.62
16GB G.Skill RipjawsZ 2133MHz
Corsair AX1200 PSU
Samsung Spinpoint F3 1TB
Noctua NH-D14
Windows 7 x64

Being both a spiritual follow-up to the X58 and Sandy Bridge on steroids we've tried to cover as many models as possible when building our results graphs. However as we haven't always got everything to hand, and because the software we use for benchmarking is updated pretty regularly we don't always have comparable results on hand, so some graphs are bigger than others.

Finally as we have some non-Intel boards on hand we're leaving the i7-3960X at stock settings for all of our testing. So for this particular processor that means a base clock of 3.3GHz and a Turbo frequency of up to 3.9GHz.

Let's get down to it.

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Intel Core i7-3960X Review

If you're one of those people who skips straight to the results, then shame on you, and it's worth reiterating, these are STOCK settings in our testing.


CPU Benchmarks

When looking at your current setup and wondering if an upgrade is necessary it's easy to forget how much technology advances. A perfect example of it is right here with the i7-3960X when compared against its 32nm brother the i7-990X. Or indeed anything else in the graph. This is ridiculously quick in the AIDA testing. So much so that neither the Hexcore power of the i7-990X nor the huge clockspeed of the 5GHz 2600K come anywhere near it.

Memory Benchmarks

From the sublime to the ridiculous. We know that the Triple Channel of the X58, here demonstrated by another Westmere CPU the i7-970, was never quite as fast as we all hoped, and equally that the dual-channel capabilities of the Sandy Bridge was very fast indeed. So theoretically the speed of Sandy Bridge dual-channel doubled with the Quad Channel available to the X79 should have given us incredible bandwidth. Certainly here it doesn't.

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Intel Core i7-3960X Review

SiSoft Sandra

Processor Arithmetic

In the eternal battle between clock speed and architecture the i7-3960X demonstrates with aplomb that newer equals better. Not only is it the highest Dhrystone result we've ever seen, but at stock it keeps up with the heavily overclocked i7-990X. How to erase the 990Xs 1.4 GHz of clock speed benefit with a simple architecture improvement. 


Processor MultiMedia

The differences are less pronounced when we move to the Mandelbrot fractal generation of the MultiMedia test in Sandra. Obviously the SSE instruction sets used for this haven't changed and therefore a combination of available threads and pure horsepower will always win out. Even still the i7-3960X trumps the stock i7-990X, and the stock FX8150 is yet further behind.

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Intel Core i7-3960X Review

As we have a new RAM kit and a new chipset we felt it would be worth looking at how much of a difference that faster RAM can make, when compared to slower, but identically timed, RAM.

AIDA64 - RAM Speed

The read speed is the biggest thing that changes between the different speeds. This has some impact in the copy speed as one would expect, but the surprise is that the write speed doesn't change at all. Perplexing.


SiSoft Sandra - RAM Speed

The Sandra bandwidth test does give us the linear increase we'd expect to see, and certainly has a large effect upon the cache and memory bandwidth, especially at 2133MHz where the i7-3960X and G.Skill combine to give nearly 200GB/s bandwidth.

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Intel Core i7-3960X Review

PC Mark Vantage

Something strange is happening in PC Mark Vantage. Whilst the memory scores we've seen previously aren't exactly where we'd hope that they would be, nonetheless there isn't a particular reason why PC Mark is having such a difficult time in taking full advantage of the bandwidth available. This greatly affects the Memory score, which is as low as the shoddy score we saw from Bulldozer, and has ramifications in that low Memory performance hugely affects the Productivity score and final PC Mark score. We have other boards on hand and will find out if this is just part of the Intel board, or an issue with Vantage.


PC Mark 7

The much newer PC Mark 7 doesn't seem to have the issue we saw in Vantage, with the i7-3960X pumping out an enormous score for a stock system. Heck it's a big score for any system.

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Intel Core i7-3960X Review


Since we last tested with POV-Ray they have changed the benchmark algorithm, and so the only thing we can compare with is what we have to hand, which is luckily a Hexcore i7. Clocked to the same speeds as the i7-3960X we can see the pure difference in architecture, and the LGA2011/X79 combination is about 6% quicker, which makes a huge difference over a realistically sized render.


CineBench R11.5

Demonstrating how well Maxon's CineBench takes advantage of every bit of power available to it, and how much power is capable of being provided by the i7-3960X. 10.39 Pts in the CPU side of the test. 10.39!! That's 1.16 ahead of the i7-990X and the highest CineBench R11.5 score we've seen that isn't overclocked. Stunning stuff.

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Intel Core i7-3960X Review

wPrime 95

Always a stiff test of the calculative powers of your setup, wPrime95 shows the enormous amounts of horsepower the Core i7-3960X provides. The 32M result is second only to the huge overclocks on the 2600K and 990X. When compared to the stock processors it's no contest.

x264 Benchmark

The x264 benchmark measures how fast it's possible to encode some HD footage using, unsurprisingly, the x264 codec. The clip it uses is, for download size reasons, only 30 seconds long. so whilst we only have 2 extra frames encoded per second when compared to the i7-970, this can quickly add up with a more realistic size film.

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Intel Core i7-3960X Review

3D Mark 11

Starting off with 3D Mark 11, the benefits of the extra bandwidth available with the combination of PCI Express 3.0 and the i7-3960X is clear. Our GTX570 has never been quicker.


3D Mark Vantage

Vantage follows its PC Mark brother in being slightly less easy to pinpoint. The P-Score isn't particularly impressive but the X score is the highest in our graph.

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Intel Core i7-3960X Review


Such is the nature of Unigine that it once against gives us a bit of a surprise. The average frame-rate is almost identical to the FX8150, and behind the i7-950, despite the extra cores and, with Turbo mode, a similar clock speed. Results such as this are why we do the testing. Even if the results don't make sense.




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Intel Core i7-3960X Review

Alien vs Predator

We finish off with a couple of games, starting with the Giger inspired Alien vs Predator. Given how reliable this produces a 60 frame average on our GTX570, hitting 62FPS on the i7-3960X is more impressive than it sounds.

Far Cry 2

Although it doesn't come close to the extra performance of the overclocked FX8150, as it shouldn't because we're at stock, against both the stock 2500K and FX8150, as well as our GPU testing standard 4GHz i7-950, the Core i7-3960X triumphs.

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Intel Core i7-3960X Review


Hopefully you've read all of our LGA2011 reviews today. This particular one focussed upon the stock performance of the Core i7-3960X, but the conclusion will encompass our knowledge of its overclocking capabilities too, which you can see in the ASUS Rampage IV Extreme and Gigabyte X79 UD5 reviews.

When we originally reviewed the X58 i7-990X the results were so outstanding that we wondered if Intel had almost set an untouchable benchmark. Especially when you consider that we knew the next top of the range LGA2011 CPU wouldn't be a reduction in the nanometre process, nor would have extra cores, and Intel are notorious for not pushing their processor speeds to the levels they can actually obtain. All we can say to that is, oh ye of little faith.

The Intel Core i7-3960X is as far ahead of the i7-990X as that is ahead of the i7-950.

Even a cursory glance through our stock results shows how capable the i7-3960X is. Probably the most surprising ones are when it's up against the heavily overclocked processors, because even the stock speeds of the i7-3960X are sufficient to stay close to them, or in some tests even pass. The Sandra Processor tests are particularly indicative of this, as is the CineBench result. It doesn't really matter what you throw at the i7-3960X, it handles everything with aplomb. The harder the test, the better it seems to perform. If that wasn't sufficient then when it's overclocked it's even more amazing, smashing nearly every record we have.

A small word about the motherboard too. Despite their claims about "Extreme" boards, we all know that Intel motherboards tend to be on the conservative side. We love the looks, we like the comprehensive labelling and we absolutely adore the 'Back to BIOS' button which is so far ahead of the other "recovering from a failed overclock" solutions we've ever seen that we want it on every future board please.

In fact we can only think of two things that are slightly disappointing. Firstly the memory performance on this particular board, and to a certain degree in general, isn't as stunning as we hoped it would be. It fits in between the scores from the Z68 and X58 chipsets and the RAM speed doesn't seem to change the bandwidth available to write actions. Secondly we've got greedy with the Sandy Bridge CPUs and would have liked to have seen the 5GHz barrier broken on air. Although considering we've still got a 4.7GHz 12 thread CPU, it's a tiny complaint.

No we're not going to complain about the eye-watering price. All premium Intel CPUs have always been around the £1000 mark, and in the case of the i7-3960X its performance absolutely justifies such a high price tag. Even better it's actually retailing for a, relatively, reasonable £770. The long and short of it is that if you absolutely must have the very best, and even if you've just brought a shiny i7-990X, the i7-3960X is still fast enough to warrant a purchase.

It's an absolutely stunning CPU and, despite the premium price, definitely worthy of our Gold Award.


Thanks to Intel for supplying the Core i7-3960X for review. Discuss in our forums.