Intel Core i7-3960X Sandy Bridge-E Performance Review November 14, 2011

With 6 cores, 15MB of cache, and support for quad-channel DDR3-1600 memory, the Core i7-3960X sounds like quite a catch. Want to know more about it and how it performs? Read on!

Introduction

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Today marks the launch date for Intel’s Sandy Bridge-E line of processors, a new family of high-end Core i7 products based on the LGA 2011 platform. This new socket is poised to replace the existing LGA 1366 specification used by the more powerful Nehalem and Westmere parts from the past couple years, specifically Bloomfield and Gulftown, the Core i7-9xx+ line of CPUs. That’s not to be confused with the LGA 1156 socket that was also used by some Nehalem Core i7s (Lynnfield), nor its successor, the LGA 1155 socket used for existing Sandy Bridge processors from the Core i7-2x00 series. LGA 1155 will stick around for at least another year to support the upcoming 22 nm Ivy Bridge processors, which should become available in early 2012.


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Intel's Core i7 CPU line-up
Available as of the release of Sandy Bridge-E
CPU	Process	Code-name	Clock Speed	Max Turbo	Cores / Threads	L3 Cache	Memory	Max TDP	Unlocked?	Graphics?	Price
i7-3960X	32-nm	Sandy Bridge-E	3.3GHz	3.9GHz	6/12	15MB	4-channel DDR3-1600	130W	Yes	No	$1050
i7-3930K	32-nm	Sandy Bridge-E	3.2GHz	3.8GHz	6/12	12MB	4-channel DDR3-1600	130W	Yes	No	$600
i7-3820	32-nm	Sandy Bridge-E	3.6GHz	3.9GHz	4/8	10MB	4-channel DDR3-1600	130W	Partially	No	TBD (Q1 2012)
i7-2700K	32-nm	Sandy Bridge	3.5GHz	3.9GHz	4/8	8MB	2-channel DDR3-1333	95W	Yes	Yes	$370
i7-2600K	32-nm	Sandy Bridge	3.4GHz	3.8GHz	4/8	8MB	2-channel DDR3-1333	95W	Yes	Yes	$320
i7-2600	32-nm	Sandy Bridge	3.4GHz	3.8GHz	4/8	8MB	2-channel DDR3-1333	95W	No	Yes	$300
i7-2600S	32-nm	Sandy Bridge	2.8GHz	3.8GHz	4/8	8MB	2-channel DDR3-1333	65W	No	Yes	$310
i7-990X	32-nm	Gulftown	3.46GHz	3.8GHz	6/12	12MB	3-channel DDR3-1066	130W	Yes	No	$999
i7-980	32-nm	Gulftown	3.33GHz	3.6GHz	6/12	12MB	3-channel DDR3-1066	130W	No	No	$580
i7-970	32-nm	Gulftown	3.2GHz	3.6GHz	6/12	12MB	3-channel DDR3-1066	130W	No	No	$550
i7-960	45-nm	Bloomfield	3.2GHz	3.46GHz	4/8	8MB	3-channel DDR3-1066	130W	No	No	$290
i7-950	45-nm	Bloomfield	3.06GHz	3.3GHz	4/8	8MB	3-channel DDR3-1066	130W	No	No	$260
i7-870	45-nm	Lynnfield	2.93GHz	3.6GHz	4/8	8MB	2-channel DDR3-1333	95W	No	No	$290
All prices cited from Newegg as of 11/14/11

Notes

As you can see, the new Core i7-3960X carries a similar price tag (slightly inflated over Intel’s citation of $990 per 1,000 units) and TDP rating as the i7-990X 6-core Gulftown CPU it is replacing, but brings more aggressive Turbo boosting, a higher cache, and of course the support for quad-channel memory. There will also be a much more attractively-priced 6-core Sandy Bridge-E chip, the i7-3930K, with nearly as much L3 cache and an unlocked multiplier. On the next page, you’ll read more about the features of Sandy Bridge-E processors and what the numbers in this chart actually mean.

Core i7-3960X features explained

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The 2nd-generation Intel Core i7 Extreme Edition processor is described as “super-smart, ultra-threaded, and absolutely uncompromising” by its marketing mumbo-jumbo. So what does that really mean? Well, it supports Turbo Boost for dynamically increasing the CPU clock speed when needed, Hyper-Threading to process two tasks per each of its six cores, and it is the first to support quad-channel RAM configurations. It has completely unlocked multipliers for overclocking flexibility, the largest amount of on-board cache memory of any Intel processor, and the companion X79 chipset supports 40 lanes of PCI-express bandwidth for true 2x16 SLI and CrossFire setups. Finally, it’s debuting alongside Intel’s brand new liquid-cooling solution, consisting of a waterblock, reservoir/pump, and heatsink/fan in closed, pre-assembled system that is simple to install.

If any of those things interest you, we’ll be going into more detail on them right now -- otherwise, you might just skip ahead to the benchmarks and conclusion.


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Socket LGA 2011 & X79 Express Chipset

As mentioned on the previous page, these new high-end Core i7 processors (AKA Sandy Bridge-E) are using Intel’s latest LGA 2011 specification. Aside from the obvious coincidence with the year it’s being released, it also literally means there are 2,011 pins on the motherboard that come in contact with the bottom of the CPU. If you don’t believe me, you can count it in the picture on the previous page!

This new socket, along with the accompanying X79 Express chipset, carries with it support for quad-channel DDR3 RAM and up to 40 PCI-Express lanes. This provides for a massive boost in available bandwidth on both fronts, which is good news for everybody, whether you’re concerned with your workstation or gaming rig. Granted, most users’ setups don’t even approach the bandwidth limits of existing platforms, but enthusiasts and professionals alike will certainly enjoy the prospect of 16x16x8 Tri-SLI or combined 51.2 GB/s of memory throughput.

Six processor cores on 32-nm process

Like the first generation of high-end Core i7 processors (code-named Gulftown), the i7-3960X and the i7-3930K both have six physical cores on one chip with a TDP rating of 130W. That’s the same amount of power draw (and thus heat production) as the quad-core Bloomfield chips, but the difference lies in the switch to a 32-nm process from 45-nm. That’s the beauty of progression in fabrication technology -- you can get more performance for the same costs because everything becomes smaller and [comparatively] cheaper to produce. We’ll be waiting a bit longer on the switch to 22-nm, though, which will be coming with the Ivy Bridge CPUs early next year that will replace the mainstream Sandy Bridge line (and eventually this SNB-E line with IVB-E!).

Turbo boost

In not so many words, Turbo Boost is used to dynamically increase the clock speed of the Core i7 processor whenever the workload demands it. It’s basically the opposite of Intel’s Speed-Step tech, which will reduce power and lower the clock speed of the CPU whenever it’s not being used, to save energy and cut down on heat. They’re two sides of the same coin, constantly adjusting the Core i7 processor based on your computing needs at any given time. You can disable them, of course, if you’d prefer more consistent performance at your fingertips.

Hyper-threading

This bullet point has been around since the Pentium 4 era, when dual-core processors didn’t exist and Intel decided to create a second “virtual” core on their CPUs to promote multi-tasking. Hyper-threading basically allows the CPU to handle twice as many application threads as it has processing cores. So, for example, the i7-3960X can handle 12 threads with its 6 physical cores, the i7-2700K 8 threads with its 4 cores, etc.

It sounds like a great thing in theory, yet unless you’re running half a dozen processor-intensive applications while you play games, it’s not going to be of much use. Unfortunately, there still aren’t very many individual games and applications that make use of 4 cores simultaneously, let alone 6, so being able to run 8 or 12 threads at once remains more of a curiosity or point of boasting than anything. Hopefully, with most new CPUs these days being quad- or hexa-core ones, we should be seeing more and more programs use them as time goes on. For gaming, I’ll bet we see a huge spike in multi-thread usage once the next generation of consoles comes out, provided they continue to try to push the envelope of hardware efficiency.


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New liquid cooling solution

Starting with the Sandy Bridge-E family of high-end Core i7 processors, Intel is no longer bundling a heatsink/fan combo into the retail package. Perhaps they finally realized that anybody spending anywhere from several hundred to a thousand dollars on a CPU is just going to opt for a higher-quality aftermarket cooler anyway, so they decided not to bother trying to force a stock one on them. They’ve partnered with Asetek to create a high-quality liquid cooling solution that is compatible with all Sandy Bridge and upcoming Ivy Bridge processors on any of the LGA 2011/1155 or 1366/1156 sockets. It’s a fully-enclosed package with copper waterblock, pump, radiator, and propylene glycol reservoir and comes with a 120mm fan, as pictured above.

Intel estimates that one in particular will cost between $85-100 at retail, but if that’s too much for you, or you’re not interested in overclocking, there will also be a barebones Intel-brand heatsink/fan combo for LGA 2011 that will cost less than $20. Of course, there will also be plenty of other choices across the spectrum from cheap heatsink/fans to more expensive all-in-one liquid-cooling solutions from third parties such as Corsair, Antec, Cool-It, and Cooler Master, among others.

System Setup

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Intel Core i7-920 (2.66GHz stock)
6GB (3x2GB) OCZ Gold @ DDR3-1333 speeds
EVGA X58 3-Way SLI

Intel Core i7-3960X Extreme Edition (3.3GHz stock)
16GB (4x4GB) Corsair Vengeance @ DDR3-1600 speeds
Intel Extreme DX79SI

2x AMD Radeon HD 6870 in Crossfire
Catalyst 11.10

Western Digital Caviar Black 1.5TB/1TB

Windows 7 Ultimate 64-bit Service Pack 1

Benchmarks

Crysis 2
Battlefield 3
Sid Meier’s Civilization V
Metro 2033
Total War: Shogun 2
3DMark Vantage
3DMark11
Cinebench 10 & 11.5
WinRAR v4.01
DivX Plus
POV-Ray v3.62 & v3.7

Crysis 2 performance

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Times Square timedemo

Battlefield 3 performance

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Thunder Run opening

Battlefield 3 Min/Max FPS
	720p Low settings	16x10 High settings	1080p Ultra settings
Core i7-3960X Stock	Min: 195, Max: 201	Min: 66, Max: 117	Min: 53, Max: 130
Core i7-3960X Turbo Off	Min: 121, Max: 201	Min: 107, Max: 201	Min: 52, Max: 132
Core i7-3960X @ 4.8GHz	Min: 196, Max: 202	Min: 104, Max: 201	Min: 53, Max: 132
Core i7-920 Stock	Min: 176, Max: 201	Min: 102, Max: 201	Min: 27, Max: 67
Core i7-920 @ 3.6GHz	Min: 119, Max: 199	Min: 108, Max: 199	Min: 51, Max: 133

Notes

You’re probably left scratching your head at these results, and believe me, I am, too… However, I repeated these tests several times to ensure consistency (as much of a pain that is, with the BF3 campaign crashing just about every time I tried to change the settings or load a checkpoint), and they remained true to what you see here. Of course, I’m referring to the fact that the i7-3960X at stock settings performing abnormally unwell at 1680x1050 with High settings, coming in with framerates well below those of every other configuration, including the i7-920. It’s also a little bit slower overclocked than with Turbo disabled, which is not how it should go. Then you have both the i7-3960X with Turbo off and the overclocked i7-920 came in well below the mark at 720p with Low settings (I’m assuming 200 FPS is the maximum for the Frostbite engine to output).

I have no explanation as to why this might be, but I suppose anything is possible when dealing with a game engine that causes some people to have better performance when they disable hyper-threading. We ought to just take the results of the first two tests with a grain of salt and mark it down to some obscure glitches or instabilities in Battlefield 3 using certain hardware and software configurations -- there’s certainly no shortage of those with that game! On the bright side, the results from the 1080p Ultra test are comfortably dull, as GPU limitations cause near-identical framerates for all but the stock i7-920.

Sid Meier’s Civilization V Performance

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Notes

The first two benchmarks on this page are built-in to the game and accessed by command line argument. The latter one is a measurement of the time it takes between turns of a mature game of Civ V, while the AI players’ actions are being processed. More specifically, this was turn 419 of a 10-player archipelago map, with everyone still in the running. It’s quite interesting to learn exactly how much time you spend waiting in between turns while playing, and how much difference a faster CPU can make.

Total War: Shogun 2 Performance

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Metro 2033 Performance

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Prologue shootout

Metro 2033 Min/Max FPS
	720p Low settings	16x10 High settings	1080p Very High settings
Core i7-3960X Stock	Min: 75, Max: 176	Min: 43, Max: 152	Min: 26, Max: 88
Core i7-3960X Turbo Off	Min: 64, Max: 175	Min: 38, Max: 152	Min: 28, Max: 87
Core i7-3960X @ 4.8GHz	Min: 88, Max: 192	Min: 51, Max: 160	Min: 26, Max: 99
Core i7-920 Stock	Min: 46, Max: 148	Min: 32, Max: 130	Min: 22, Max: 87
Core i7-920 @ 3.6GHz	Min: 65, Max: 152	Min: 40, Max: 152	Min: 24, Max: 103

3DMark Vantage

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3DMark 11

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3D Image Rendering Performance

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Cinebench

Persistence of Vision Ray-tracer

Video Encoding & Data Compression Performance

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DivX Plus

WinRAR

Conclusion

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While I regret not having access to more CPUs to be able to compare it to, there’s no questioning that Intel’s new Core i7-3960X is nothing less than a beast. It performed exceptionally well in every benchmark even at stock settings (which actually means up to 3.9GHz) and is an incredible overclocker, offering instant access to even more power, especially if you opt for the liquid cooling.

Using the Intel DX79SI motherboard’s overclocking assistant that is built in to the BIOS, it was a breeze to reach the 4.6GHz I tested with. Considering they claim it can easily reach 4.8GHz, I have no doubt a proficient overclocker could tweak it all the way up to 5GHz, if not higher. There’s even a very nifty Windows app called Intel Extreme Tuning Utility that offers in-depth options for overclocking the CPU and memory, as well as a full monitoring suite, to rival anything you can see and do from within the BIOS itself.




However, even though the 6 cores and 12 threads make mincemeat of the rendering/encoding/compression benchmarks that are specifically designed to make use of them, the game and 3DMark tests show that most people will invariably be limited by the GPU(s) when you crank up the graphics settings (which everyone would do, of course). The power of the i7-3960X is wasted on dual-Radeon HD 6870s in CrossFire (about the equivalent of a single GeForce GTX 580), as evidenced by my older, Core i7-920 keeping pace in many of the tests when overclocked to a competitive 3.6GHz.

Although, considering the i7-3960X represents the highest of high end in CPUs, it stands to reason that it should be paired with similar GPU horsepower, perhaps dual-GTX 580s or triple-GTX 560s, at least. Even still, you probably wouldn’t be missing much if you went with a much-cheaper quad-core Sandy Bridge instead, at least in terms of actual in-game performance.


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