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Intel Core i7-3820 Processor Review - Quad-Core Sandy Bridge-E under $300

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Subject: Processors
Manufacturer: Intel

A New Chip for a New Year

When Intel launched the Sandy Bridge-E platform in November, there were three processors listed on the specification sheet.  The Core i7-3960X is the flagship, 6-core processor with the ~$1000 price tag, the Core i7-3930K still had 6-cores but a much lower cost and similar clock speeds and the Core i7-3820 was the only quad-core option and was listed for a Q1 release.  We reviewed the Core i7-3930K in December and found that it offered nearly the same performance as the more expensive unit at about half the price. 

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Today we are getting a preview of the Core i7-3820 that will be released likely in early February and will come with a much more reasonable price tag of $285 to fill out the LGA2011 socket.  The question that we must ask then is can the quad-core Core i7-3820 compete against the currently available quad-core Sandy Bridge parts that fit in the widely available LGA1155 socket?  We not only have to consider performance but also the features of each platform as well as the total cost. 

Same Feature Set, New Die

While most of the features of the Core i7-3820 are going to be identical to those of the previous SNB-E processors we have seen, there are some important differences with this chip.  Let's see what is familiar first.  The Core i7-3820 is based on the Sandy Bridge-E design that works on the LGA2011 socket and the X79 chipset and motherboards currently on the market.  It includes a quad-channel memory controller and 40 lanes of PCI Express that are actually capable of PCIe 3.0 speeds.  HyperThreading is still enabled so you are getting the benefit of being able to run twice as many threads as you have cores. 

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There are some very important changes on this CPU as well though starting with a quad-core design.  This directly pits this Sandy Bridge-E part against the currently existing Sandy Bridge processors running on the Z68/P67 chipset and LGA1155 socket.  Also, the L3 cache on the Core i7-3820 is at 10MB, 5MB less than the Core i7-3960X and 2MB less than the Core i7-3930K.  We are basically talking about a processor that bridges the gap between the original SNB and newer SNB-E parts and it creates some interesting battles and comparisons. 

Continue reading our review of the Core i7-3820 Sandy Bridge-E CPU!!!

Interestingly, this quad-core SNB-E part is not simply a chip with more cores disabled but instead is a completely new die built on the same 32nm process.  While the Core i7-3960X and i7-3930K have a transistor count of 2.27 billion and a die size of about 435 mm2, the Core i7-3820 is based around 1.27 billion transistors and a 294 mm2 die - a significant reduction. 

Let's look at the relevant CPU specifications:

  • Core i7-3930K (SNB-E)
    • Cores: 6
    • Base: 3.2 GHz
    • Turbo: 3.8 GHz
    • Cache: 12MB
    • Memory: Quad channel
    • Price: $555
  • Core i7-3820 (SNB-E)
    • Cores: 4
    • Base: 3.6 GHz
    • Turbo: 3.9 GHz
    • Cache: 10MB
    • Memory: Quad channel
    • Price: $285
  • Core i7-2700K (SNB)
    • Cores: 4
    • Base: 3.5 GHz
    • Turbo: 3.9 GHz
    • Cache: 8MB
    • Memory: Dual channel
    • Price: $369
  • Core i7-2600K (SNB)
    • Cores: 4
    • Base: 3.4 GHz
    • Turbo: 3.8 GHz
    • Cache: 8MB
    • Memory: Dual channel
    • Price: $319

AT $285, the Core i7-3820 actually undercuts both the Core i7-2600K and the Core i7-2700K while offering more cache, higher base and turbo clock speeds as well as twice as many memory channels.  The downside is that your X79 motherboard is going to cost more - base X79 options start around $220 while you can get Z68 motherboards for just over $100, $150 for an "enthusiast-class" option. 

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Original Sandy Bridge on the left, new Sandy Bridge-E on the right

Another interesting difference with the Core i7-3820 and the other three CPUs listed above is that it is NOT a fully unlocked processor.  Like other Turbo Boost enabled processors in Intel's Sandy Bridge processors the i7-3820 can be set to a multiplier that is four steps higher than the top Turbo frequency.  So, out of the box, the quad-core SNB-E part will be able to run at 4.3 GHz (single core active), 400 MHz higher than the 3.9 GHz top default Turbo frequency.  There are ways to get higher than this with the 3820 that we'll cover in our overclocking page a bit later. 

Our testing configuration for this testing was identical to that used in the previous Sandy Bridge-E review. 

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Highest clock speed with all cores in use

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Highest clock speed with a single core in use

  • Intel Core i7-3820 (Sandy Bridge-E)
  • Intel DX79SI X79 Motherboard
  • Intel water cooler
  • 4 x 2GB DDR-1866 Corsair Vengeance (running at DDR3-1333)
  • Intel X25-M G2 160 GB SSD
  • GeForce GTX 285 Graphics card
  • PC Power and Cooling 1200 watt PSU
  • Windows 7 SP1 64-bit

What are the key comparisons do we want to watch out for? 

  • Core i7-3930K vs Core i7-3820 - In the battle of the $285 and the $555 Sandy Bridge-E processors, we know who should win, but is it by enough to warrant the price difference?
  • Core i7-2600K vs Core i7-3820 - Does the updated architecture of Sandy Bridge-E make any performance differences thanks to the larger cache, additional memory channels and slightly higher clock speeds?  This will help us decide if users on a moderate budget would be better off with LGA2011 or LGA1155 platforms.
  • Core i7-3820 vs AMD FX-8150 - Okay, let's give the Bulldozer architecture yet another try here especially considering that they are so similarly priced!
January 4, 2012 | 07:30 AM - Posted by Jared (not verified)

Great Work PCPER.

January 4, 2012 | 08:12 AM - Posted by Prodeous (not verified)

Very nice review. I will admit makes me want to get it over the 2600K.

With regards to the review. I was wondering if there is a way to make the result charts more readable?

The main thing is better grouping of Intel and AMD cpus? I know this is more or less add the newest CPU at the top, but when I jump from page to page and try to compare it to other CPUs it makes it difficult to quickly compare between them.

Possible area of improvement is just colour code it. AMD green, Intel Blue, currently tested Red? Or any other colour scheme.

Beyond that I'm curious about the Blender benchmarks, especially with Blender 2.61 having better multithreading and new rendering engine called Cycles which is fully ray tracked engine unlike current.

What ever you guys do or not do I just want to say. You guys are doing an amazing job.

Polish Canuck - Prodeous.

January 4, 2012 | 10:10 AM - Posted by Ryan Shrout

Prodeous, thanks for the comments. I think you are right on the graphs and it is something we have tried to figure out in the past but honestly, my Excel-foo is just too weak... We'll try again soon!

As for Blender, we are going to completely re-do our CPU test bed soon and I'm sure we'll update it then.

January 4, 2012 | 11:00 AM - Posted by Nebulis01

I think this will be a decent way to upgrade from my Q9650 :)

Thanks for the great review!

January 4, 2012 | 02:31 PM - Posted by hechacker1 (not verified)

Any thoughts on the continued support of LGA 1155 vs 2011? In the long term, I'd think the 2011 platform is a better choice. You get PCI-E 3.0 for next gen GPUs, and a socket that potentially carries you onto a Ivy-E chip with 8-cores? A lot of speculation I'm sure.

Care to comment? btw love the podcast.

January 4, 2012 | 03:07 PM - Posted by Dreadteir

As a enthusiast, I think I like what I see in the SNB-E.

For my build later this year I was looking at the 2600K with a water cooler, a $220 Motherboard and populating all 4 DIMM slots. This processor will likely have me reevaluating what I do with this system as the x79 platform is more robust than the Z68.

Perhaps I will change my mind again after I see what Ivy Bridge brings to the table though.

Excellent review Ryan, and I have to agree with Prodeous both about the charts and the continued excellence.

Cheers,

Dreadteir

January 4, 2012 | 05:58 PM - Posted by Anonymous Coward (not verified)

The high end SB-E processors are enough of a shitty value themselves, but this takes the cake. You'd have to be a grade A moron to buy this over something like a 2600K or 2700K. Either you have the money to blow on a 6core SB-E, or you don't. This in between bullshit gets you SB performance and SB-E prices.

January 4, 2012 | 06:58 PM - Posted by iczerjones (not verified)

...with twice the memory bandwidth and more PCIe. It definitely fills a specific niche, but I'm not sure I would heckle a potential buyer as a 'moron'.

February 10, 2012 | 01:10 PM - Posted by Kilobit (not verified)

Umm only an uneducated idiot would say that. On a 2600k 0r 2700k your pci-e lanes have limited frequencies due to the very mild on chip intergrated graphics. I'll explain this in layman's terms... If you want to run multiple video/graphics cards your pci-e multipliers are limited to 8x/8x or 16x/4x if you use the SB-E chips without intergrated graphics you will be able to run 2 video/graphics cards @16x each and a third card @8x.Plus the SB-E chips fully support Pci-e 3.0 although regular SB chips are able to run pci-e 3.0 they do not fully support pci-e 3.0 because 3.0 came out much later than the release of the SB chips therefore they were not designed to run it.

January 5, 2012 | 05:16 AM - Posted by Robert Johnson (not verified)

Good review. I just wish Intel would release this CPU before February

January 5, 2012 | 08:10 AM - Posted by Octavean (not verified)

Excellent review and quite the feather in the cap of Pcper as you are one of the few to review all three Sandy Bridge-E processors. In fact I know of no other at this time that has. Most so far have only reviewed the Core i7 3960X. I think Anandtech only has a review of the 3960X and now the 3820 too.

Personally I was waiting for C2 stepping but the Core i7 3820 looks to be quite reasonable once its released. I still feel like X79 motherboards are missing features though. I’d like to see an updated chipset that has the features we were expecting out of the X79 (12 Intel SATA ports 3G + 6G, native Intel SRT and so on).

January 5, 2012 | 08:42 AM - Posted by Anonymous (not verified)

The biggest issue for me with this chip is the TPD. 130w vs. 95w makes this a no go for me. The minimal gains vs. the 2600k are not woth the added power consumption, especially when overclocked.

January 5, 2012 | 04:22 PM - Posted by tellis006

This was a great review, I also have a question, I have a 990X,GTX480,GI Assassin Mobo, with GB revodrive, while my rig is not quite a year old it is fast, the fastest I've ever had do you think I would benefit from a upgrade or should I wait till the next round. I have moved up the ladder selling and buying so I can have a nice rig. I have almost a thousand movies and tens of thousands of songs and use my computer for encoding mostly and play skyrim and COD4, and BF3 ?

January 6, 2012 | 08:01 AM - Posted by perfectshot (not verified)

Awesome! Can't wait to leave the Core 2 Duo era. Sure, I've got a quad now but the rest of the PC will be five years in March.

I wonder what difference the RAM speeds will make (1600 vs 1333)... Photomatix doesn't rely on CPU power as much as memory speed.

January 6, 2012 | 08:08 AM - Posted by cipher_nemo (not verified)

Just an FYI: your pricing column lists "(1k USD)", which should obviously be just "(USD)".

January 6, 2012 | 09:08 AM - Posted by superxero (not verified)

I imagine a lot of people who are considering the 3820 are currently running i7 920 rigs. Could you add the 920 to the benchmarks for comparison? It might be helpful to see whether the upgrade is worth it or not.

January 7, 2012 | 03:01 AM - Posted by rrr (not verified)

I don't think it's worth it over 2600k, unless you plan to go 3930k soon.

January 8, 2012 | 09:49 AM - Posted by Anonymous (not verified)

Am I missing something, but your charts show good metrics for
the Core i5 s, several times beating the i7's. What's the
answer? Channels? USB3? PCI?

January 17, 2012 | 09:27 AM - Posted by Eldonko (not verified)

SLI tests? Would have been nice to see the difference between 3820 and 2600k w/ multi-GPU.

February 1, 2012 | 03:22 AM - Posted by Anonymous (not verified)

In Romania is listed as "available for purchase" online at PcGarage.Price is exactly 300 euros.
http://www.pcgarage.ro/procesoare/intel/i7-3820-36ghz-box/

November 16, 2012 | 08:56 AM - Posted by Anonymous (not verified)

the Core i5 s, several times beating the i7's. What's the

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