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Intel Core i7-3820 Quad-Core Sandy Bridge-E CPU Review
Date: Jan 16, 2012
Author: Marco Chiappetta
Introduction and Specifications

A few weeks back, we took a look at the Core i7-3960X, Intel’s first desktop processor to feature the company’s Sandy Bridge-E microarchitecture. If you're unfamiliar with the chip, Sandy Bridge-E is the ‘tock’ in Intel’s tick-tock release schedule cadence that bridges the gap between first-gen Sandy Bridge-based processors like the Core i7-2700K and next year’s Ivy Bridge microarchitecture. Sandy Bridge-E shares many of the same features of the original Sandy Bridge microarchitecture, but as the “E” denotes, SBE is a more extreme derivative, targeted at enthusiasts.

In our launch coverage of the Intel Core i7-3960X, we take a deep-dive look at Sandy Bridge-E and detail many of its features, like its 40 integrated PCIe 3.0-class lanes, quad-channel memory controller configuration, new socket and chipset, 32nm manufacturing process, and many others. We’d highly recommend checking out that article, because it lays all of the groundwork necessary to fully appreciate the processor we’ll be showing you today, the Core i7-3820.

We briefly discussed the Core i7-3820 in our Core i7-3960X coverage, but didn’t have a chip on hand for testing. The Core i7-3820 is based on the very same die as the higher-end Core i7-3960X, but two of its cores (and some cache) have been disabled. Whereas the Core i7-3960X has six active cores and 15MB of shared SmartCache, the Core i7-3820 has four active cores and 10MB of shared cache. There are a few other difference as well, but fundamentally the two processors are very similar. Full specifications are below, followed by a few more details, performance, and even a little overclocking...

Intel Core i7-3820 Processor
Specifications & Features

  • Core Frequency:
    3.6GHz (Up To 3.9GHz w/ Turbo)
  • QPI Speed:
  • TDP (Thermal Design Power):
  • Number of CPU Cores:
     4 (8 Threads w/ HT)
  • Intel SmartCache:
  • L2 Cache:
    1.5MB (256K x 6)
  • Processor input voltage (VID):
  • .032-micron manufacturing process
  • Shared Smart Cache Technology
  • Enhanced Intel SpeedStep Technology (EIST)
  • Extended HALT State (C1E) Enabled
  • Execute Disable Bit (XD) Enabled
  • Intel 64 Technology
  • AES-NI: Processor instructions
  • Intel Virtualization Technology (VT)
  • Packaging - Flip Chip LGA2011
  • Total Die Size: Approximately 434.7mm2
  • Approximately 2.27B Transistors
  • Price - $285
Quad-Core Processing: Runs 4 independent processor cores in one physical package

Base Processor Frequency: 3.60 GHz

Massive PCI Express Bandwidth: 40 lanes of PCIe supported through the processor

Intel Turbo Boost Technology: Dynamically increases the processor frequency up to 3.90GHz when applications demand more performance. Speed when you need it, energy efficiency when you don’t.

Intel Hyper-Threading Technology: 8 threads provide unprecedented processing capability for better multi-tasking and threaded applications. Do more with less wait time.

Intel Smart Cache: Up to 10MB of shared cached allows faster access to your data by enabling dynamic and efficient allocation of the cache to match the needs of each core significantly reducing latency to frequently used data and improving performance.

Overclocking Enabled: Core (Turbo) and DDR3 ratios are partially unlocked for ease of overclocking

Integrated Memory Controller: Supports 4 channels of DDR3-1600 memory with 1 DIMM per channel. Support for XMP memory. See this site for certified XMP memory.

Intel LGA 2011 Sandy Bridge-E Processor, Top and Bottom

The Core i7-3820 differs from the Core i7-3960X in a few ways. For one, the 3820 is not an ‘Extreme Edition’ part, which is to say it is not fully unlocked. Rather, the Core i7-3820 is only partially unlocked. Like first-gen, non-K series Sandy Bridge-based processors (with Turbo mode support), the Core i7-3820’s peak Turbo multiplier can be increased by only four speed bins above stock, for a maximum of 4.3GHz, disregarding the effects of base clock manipulation.  More on overclocking a little later, though.

The Core i7-3820’s frequencies also differ from the Core i7-3960X. The 3960X has a base clock speed of 3.3GHz, with a max Turbo clock of 3.9GHz. The Core i7-3820 offers the same 3.9GHz max Turbo frequency, but its base clock is somewhat higher at 3.6GHz. That extra 300MHz may sound nice but in reality, provided you've got adequate power and cooling, Sandy Bridge or SBE-based processors rarely operate at their base clock frequency and almost always are in some state of Turbo.

Physically, the Core i7-3820 looks just like other Sandy Bridge-E based processors for the LGA2011 socket and they require the very same X79 Express chipset and cooler, and have the same 130W TDP.

Considering the Core i7-3820 offers “only” four cores, you may be wondering what, if any, benefits it offers over first-gen Sandy Bridge-based processors. Well, the Core i7-3820 offers more cutting-edge integrated PCI Express connectivity, more memory bandwidth (quad-channel vs. dual-channel), more cache, and it’s paired to Intel’s latest chipset. What those benefits offer in terms of additional performance, is what we’ll try to show you on the pages ahead...

Test Setup and PCMark 7

Test System Configuration Notes: When configuring our test systems for this article, we first entered their respective system BIOSes / UEFI and set each board to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set the memory frequency to the maximum officially supported frequency for the given platform. SSDs were then formatted, and Windows 7 Ultimate x64 was installed.

Intel Core i7-3820, Top and Bottom

When the Windows installation was complete, we updated the OS, and installed the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled and we installed all of our benchmarking software, performed a disk clean-up, cleared temp and prefetch data, and ran the tests.

HotHardware's Test Systems
Intel and AMD - Head To Head

System 1:
Intel Core i7-3690X
(3.33GHz - Hex-Core)
Intel Core i7-3690X
(3.33GHz - Hex-Core)

Asus P9X79 Deluxe
(X79 Express Chipset)

4x4GB G.SKILL DDR3-1866
(@ 1600MHz)

GeForce GTX 280
On-Board Ethernet
On-board Audio

OCZ Vertex 3 MaxIOPS

Windows 7 x64

System 2:
Intel Core i5-2700K
(3.3GHz - Quad-Core)

Asus P8Z68-A Pro
(Z68 Express Chipset)

2x4GB G.SKILL DDR3-1866
(@ 1333MHz)

GeForce GTX 280
On-Board Ethernet
On-board Audio

OCZ Vertex 3 MaxIOPS

Windows 7 x64

System 3:
Intel Core i7-990X
(3.43GHz Hex-Core)

Gigabyte EX58-UD4
(X58 Express Chipset)

3x4GB G.SKILL DDR3-1866
(@ 1333MHz)

GeForce GTX 280
On-Board Ethernet
On-board Audio

OCZ Vertex 3 MaxIOPS

Windows 7 x64

System 4:
AMD FX-8150
(3.6GHz Eight-Core)

Asus CrossHair V Formula
(AMD 990FX Chipset)

2x4GB G.SKILL DDR3-1866
(@ 1866MHz)

GeForce GTX 280
On-Board Ethernet
On-board Audio

OCZ Vertex 3 MaxIOPS

Windows 7 x64

Futuremark's PCMark 7 is the latest version of the PCMark whole-system benchmarking suite. It has updated application performance measurements targeted for a Windows 7 environment and uses newer metrics to gauge relative performance. Below is what Futuremark says is incorporated in the base PCMark suite and the Entertainment, Creativity, and Productivity suites, the four modules we have benchmark scores for you here.

Futuremark PCMark 7
General Application and Multimedia Performance
The PCMark test is a collection of workloads that measure system performance during typical desktop usage. This is the most important test since it returns the official PCMark score for the system
  • Windows Defender
  • Importing pictures
  • Gaming

Video Playback and transcoding

  • DirectX 9

Image manipulation
Web browsing and decrypting

The Entertainment test is a collection of workloads that measure system performance in entertainment scenarios using mostly application workloads. Individual tests include recording, viewing, streaming and transcoding TV shows and movies, importing, organizing and browsing new music and several gaming related workloads. If the target system is not capable of running DirectX 10 workloads then those tests are skipped. At the end of the benchmark run the system is given an Entertainment test score.

The Creativity test contains a collection of workloads to measure the system performance in typical creativity scenarios. Individual tests include viewing, editing, transcoding and storing photos and videos. At the end of the benchmark run the system is given a Creativity test score.

The Productivity test is a collection of workloads that measure system performance in typical productivity scenarios. Individual workloads include loading web pages and using home office applications. At the end of the benchmark run the system is given a Productivity test score.

The Intel Core i7-3820 offered performance slightly better than the Core i7-2700K according to PCMark 7, but it trailed the higher-end Core i7-3960X overall. In the Creativity and Productivity tests, however, where the additional cores and cache of the Core i7-3960X have less of an imact, the 3820 was actually able to pull ahead of Intel's current flagship, by the slimmest of margins.
Cinebench R11.5 and POV-Ray

Cinebench R11.5 is an OpenGL 3D rendering performance test based on Cinema 4D from Maxon. Cinema 4D is a 3D rendering and animation tool suite used by 3D animation houses and producers like Sony Animation and many others. It's very demanding of system processor resources and is an excellent gauge of pure computational throughput. This is a multi-threaded, multi-processor aware benchmark that renders and animates 3D scenes and tracks the length of the entire process. The rate at which each test system was able to render the entire scene is represented in the graph below.

Cinebench R11.5
3D Rendering Benchmark

In terms of its single-thread / core performance, the Core i7-3820 Extreme Edition performs on par with the Core i7-2700K (not surprisingly). The Core i7-3820 pulls slightly ahead of the 2700K in the multi-threaded test though. The Core i7-3960X Extreme Edition and 990X, which both have more cores than the 3820, hold onto the lead.
POV-Ray Performance
Ray Tracing Benchmark

POV-Ray , or the Persistence of Vision Ray-Tracer, is an open source tool for creating realistically lit 3D graphics artwork. We tested with POV-Ray's standard 'one-CPU' and 'all-CPU' benchmarking tools on all of our test machines and recorded the scores reported for each. Results are measured in pixels-per-second throughput; higher scores equate to better performance.

POV-Ray tells essentially the same story as Cinebench. In these tests, the Core i7-3820 performs right about on par with the Core i7-2700K, but trails the Intel processors with more cores.

LAME MT and SunSpider

In our custom LAME MT MP3 encoding test, we convert a large WAV file to the MP3 format, which is a popular scenario that many end users work with on a day-to-day basis to provide portability and storage of their digital audio content. LAME is an open-source mid to high bit-rate and VBR (variable bit rate) MP3 audio encoder that is used widely around the world in a multitude of third party applications.

Audio Conversion and Encoding

In this test, we created our own 223MB WAV audio file and converted it to the MP3 format using the multi-thread capable LAME MT application in single and multi-thread modes. Processing times are recorded below, listed in seconds. Shorter times equate to better performance.

Our LAME MT benchmark will use only one or two threads depending on the test mode. As such, the additional cores of the Core i7-3960X and 990X do not come into play, and the quad-core 3820 performs exactly the same as Intel's current flagship, which offers the same peak Turbo frequencies.

SunSpider JavaScript Benchmark
JavsScript Performance Testing

Next up, we have some numbers from the SunSpoder JavaScript benchmark. According to the SunSpider website:

This benchmark tests the core JavaScript language only, not the DOM or other browser APIs. It is designed to compare different versions of the same browser, and different browsers to each other. Unlike many widely available JavaScript benchmarks, this test is:

Real World - This test mostly avoids microbenchmarks, and tries to focus on the kinds of actual problems developers solve with JavaScript today, and the problems they may want to tackle in the future as the language gets faster. This includes tests to generate a tagcloud from JSON input, a 3D raytracer, cryptography tests, code decompression, and many more examples. There are a few microbenchmarkish things, but they mostly represent real performance problems that developers have encountered.

Balanced - This test is balanced between different areas of the language and different types of code. It's not all math, all string processing, or all timing simple loops. In addition to having tests in many categories, the individual tests were balanced to take similar amounts of time on currently shipping versions of popular browsers.

Statistically Sound - One of the challenges of benchmarking is knowing how much noise you have in your measurements. This benchmark runs each test multiple times and determines an error range (technically, a 95% confidence interval). In addition, in comparison mode it tells you if you have enough data to determine if the difference is statistically significant.

All of the systems were testing using the latest version of Internet Explorer 9, with default browser settings, on a clean install of Windows 7 Ultimate x64.

The additional compute resources of the high-end Core i7-3960X are not exploited by the SunSpider benchmark either, hence the Core i7-3820 offers very similar performance here, which is to say it leads the pack right along with the other Sandy Bridge-based processors.
Crysis and ET: Quake Wars

For our next series of tests, we moved on to some more in-game benchmarking with Crysis and Enemy Territory: Quake Wars. When testing processors with Crysis or ET:QW, we drop the resolution to 1024x768, and reduce all of the in-game graphical options to their minimum values to isolate CPU and memory performance as much as possible. However, the in-game effects, which control the level of detail for the games' physics engines and particle systems, are left at their maximum values, since these actually do place a load on the CPU rather than GPU.

Low-Resolution Gaming: Crysis and ET: Quake Wars
Taking the GPU out of the Equation

The Intel Core i7-3820 performed well in our low-res game tests. Here, the Core i7-3820 outpaced the Core i7-2700K, and even managed to nudge past the Core i7-990X in the ET:QW test.
Overclocking the Core i7-3820
We also spent some time overclocking the Intel Core i7-3820. Because this processor is only partially unlocked, users are only able to increase peak Turbo mode multipliers by up to 4 speed bins, which would push core clocks up to 4.3GHz (3.9GHz stock [39 x 100] + 4 = 4.3GHz [43 x 100]). Unlike LGA1155-based Sandy Bridge processors which offer minimal base clock flexibility, however, Sandy Bridge-E chips like the Core i7-3820 have additional straps available--125MHz (1.25x), 166MHz (1.66x), and 250MHz (2.5x) to be exaxt.

Overclocking the Intel Core i7-3820
Putting the Pedal to the Metal

By bumping the BCLK to 125MHz, the Core i7-3820 will Turbo up to 4.87GHz, which unfortunately wasn't stable with our particular chip when using a CoolerMaster Hyper 212 air-cooler. Droppnig the peak multiplier to 38 and increasing the core voltage by .2v, which resulted in a peak Turbo frequency of 4.75GHz was stable.  With the processor available to run at that high a frequency, the Core i7-3820 offers some strong performance, although the higher frequency isn't enough to overtake the six core Intel processors in multi-threaded workloads.
Total System Power Consumption
Before bringing this article to a close, we'd also like to take a but about power consumption. Throughout all of our benchmarking and testing, we monitored how much power our Intel Core i7-3820-based test system was consuming with a power meter, versus other test systems we used for benchmark comparisons on the previous pages.

Total System Power Consumption
Tested at the Outlet

Our goal was to give you an idea as to how much power each configuration used while idling at the Windows desktop and while under a heavy CPU workload. Keep in mind, this is total system power consumption being measured at the outlet and not the the individual power of the CPUs alone.

With two fewer cores enabled and less active cache, it should come as no surprise that the Core i7-3820 consumes less power than its other Sandy Bridge-E based counterpart, the Core i7-3960X. Idle power consumption was similar between the two, but peak power was about 35 watts lower with the Core i7-3820. Versus the similar-performing Core i7-2700K, however, the Core i7-3820 based system uses significantly more power, not only due to the processor's additional resources and larger die, but the additional needs of the X79 platform (quad-channel memory, more PCIe lanes, etc.)

We also wanted to show you what happens to power consumption when overclocking the Core i7-3820. As you can see, with the CPU frequency cranked up to 4.7GHz (and an additional .2v being applied to the CPU), the Core i7-3820 based system pulled almost 100 additional watts from the wall. Having a good power supply is always important, but if you plan to overclock a Sandy Bridge-E based system, having a quality PSU capable of providing plenty of juice is paramount.

Our Summary and Conclusion

Performance Summary: The Core i7-3820 performed very well throughout our battery of benchmarks. Versus AMD’s flagship FX-8150, there was no contest; the Core i7-3820 was dominant. Versus Intel’s other processors, the story isn’t quite as clear. We’ll start with the Core i7-3820 / Core i7-3960X comparison. When compared to Intel’s flagship six-core Core i7-3960X processor, the quad-core Core i7-3820 offers virtually identical performance in single-threaded workloads or workloads that will tax four or fewer cores, due to the two processor’s identical peak Turbo mode frequency (3.9GHz). In highly-threaded workloads, however, that can leverage the additional resources of the Core i7-3960X, the six-core processor offers significantly more performance.

Although it has a number of technical advantages (more cache, more / faster PCIe lanes, newer platform, etc.), the Core i7-3820 performs almost identically to the Core i7-2700K, at least with the applications we used for testing. This is to be expected considering their core architecture similarities, but with workloads that can take advantage of the additional memory or PCIe bandwidth offered by the 3820, it will likely put up better numbers than the Sandy Bride-based Core i7-2700K. Conversely, the Core i7-2700K supports Intel’s QuickSync technology, whereas the SBE-based Core i7-3820 does not. So, for video encoding, the Core i7-2700K (or other Sandy Bridge-based CPU) will be superior.

Intel Core i7 and Core i7 Extreme Processor Packaging

Intel’s initial line-up of Sandy Bridge-E-based processors is outlined in the chart below. The line-up (for now) consists of three processors: the flagship Core i7-3960X, the unlocked but slightly pared down Core i7-3930K, and the Core i7-3820 we’ve shown you here. Pricing for the three processors is $990, $555, and $285, respectively.

Intel Desktop Processor Line-Up

At its $285 price point, the Core i7-3820 actually comes in somewhat cheaper than the similarly performing Core i7-2700K. That may seem like a clear win for the 3820, but when the entire platform is considered, the Core i7-3820 will actually be somewhat more expensive due to the higher cost of X79 Express chipset-based motherboards versus the Z68 and the need for quad-channel memory (versus dual-channel) to attain peak performance.

Ultimately, whether or not the Core i7-3820 makes sense for you, over the somewhat more affordable Sandy Bridge platform, is going to depend on the type of applications you run or the configuration you’re after. If you have a need for the additional memory bandwidth offered by SBE or a need for more than 32GB of memory, SBE is the way to go. Hardcore gamers who plan to run two or more high-end graphics cards would also be better served by Sandy Bridge-E’s additional PCI Express lanes and due to the fact that Intel integrated graphics aren't required. Or if you just want the latest Intel chipset, namely the X79 Express, SBE is for you.

  • Strong performance
  • 4 cores / 8 threads
  • 40 PCI Express lanes
  • Highly overclockable
  • PCI Express 3.0 ready
  • Insane memory bandwidth
  • Turbo Boost 2.0
  • Competitive price
  • High power consumption when overclocked
  • No QuickSync
  • Not faster than 2700K

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