Saturday, March 31, 2012

Intel Core i7-3820 Processor Review

Intel's Core i7-3820 processor was recently released on February 12th. Some of you might be wondering if this cheaper version of the Sandy Bridge-E processors is a better value or option to something like the i7 2700k processor. We'll do our best to outline what this processor brings to the table and then we’ll benchmark the processor to see how it stacks up against alternative processors you might be considering for your next build.
Previously Intel released two SB-E processors: the Core i7-3960x, and the Core i7-3930k. The current price for each of these is roughly $1,049 and $599 respectively. At those prices, they are definitely targeted for those with deep pockets and a need for the extreme. With the recent addition to their SB-E lineup the Core i7-3820 can be picked up for about $309. At roughly half the price of the mid range SB-E you have to wonder what Intel has done to make this one so cheap.
Here is a table that compares some of the specs for the SB-E processors.
The first thing you might notice is the base clock speed being slightly higher while the max turbo speed is right on par with the other two. Probably one of the most significant difference is the number of cores. The i7-3820 comes with 4 cores rather than the 6 cores we’ve seen in the other two SB-E processors. The L3 cache is slightly lower though it still has a large amount of cache.
The chart does not mention anything about Integrated graphics. With the introduction of Intel’s second generation i3/i5/i7 processors they came with an integrated GPU. None of the SB-E processors have integrated graphics; however we would like to point out that the SB-E processors are targeted towards enthusiasts who will most likely want dedicated graphics cards anyway. As an enthusiast myself I must say that I would rather see Intel put the money towards better, faster and more feature rich CPU’s than to put it towards integrating a GPU that I would never use.
The last thing we would like to point out has to do with Intel’s naming convention and its significance to the Core i7-3820. Processors that end with x are part of Intel’s extreme lineup which means that they have unlocked multipliers. The k suffix is indicative of their mid range processors but they still have unlocked multipliers. The i7-3820 does not end in a k or an x which means that it unfortunately does not have an unlocked multiplier.
For those of you that are unfamiliar with Intel’s production model we would like to cover what they call the Tick-Tock model. Intel designs their processors in what they call the tick-tock model where the tick is representative of manufacturing process technology while the tock is representative of improved microarchitecture.
The Sandy Bridge-E processors are part of the tock, so they have improved microarchitecture over the previous Westmere processors but they are still on the 32 nm fabrication process.
When deciding what hardware to include in your next computer it is important to identify the features you are most interested in. People ask me all the time, “What’s the best processor”. I usually follow up their question asking them what they are looking for in a computer. Most people just want a quick answer, but the unfortunate truth is it’s more complicated than that.
The X79 chipset motherboards should include PCI Express 3.0. The improvement over PCI Express 2.0 is roughly twice the speed. PCIe 2.0 was capable of 500 MB/s on each lane. So on a x16 PCIe slot it is capable of transfer speeds up to 8 GB/s in each direction. PCI Express 3.0 doubles that speed bringing it to an amazing 16 GB/s each way to total 32 GB/s of bi-directional transfer speeds. This feature will definitely leave the doors open as SSD’s increase in speed and graphics cards provide more processing power.
Another major improvement to PCI Express with SB-E processors is the number of PCIe lanes. Sandy Bridge-E processors support up to 40 lanes. This gives you the possibility of two x16 slots for running in SLI/Crossfire with one x8 slot or however you chose to configure your 40 PCI Express lanes.
Quad-Channel Memory
Quad-channel memory certainly sounds cool. In the past we’ve seen dual channel setups and then triple-channel memory configurations. Sandy Bridge went back to dual channel memory while Sandy Bridge-E bumped it up to quad-channel memory. It will be interesting to see how quad-channel memory performs in our benchmarks compared to dual-channel and triple-channel memory configurations.
L3 Cache
Another feature to consider is the amount of L3 cache on the chip. Both the i7-2600k and the i7-2700k have 8 MB of L3 cache while the i7-3820 comes with 10 MB. L3 cache plays an important role in the performance of the processor.
Intel started including the northbridge in the CPU with the introduction of Sandy Bridge processors. Here are a few other features we haven’t mentioned yet that the i7-3820 offers native support for:
-14 Hi-Speed USB 2.0 ports
-Intel Gigabit LAN Connection
-2 SATA 6 Bb/s and 4 SATA 3 Gb/s ports
The Setup
To test out our brand new Core i7-3820 processor we'll be using the ASUS P9X79 Deluxe motherboard. We have 32 GB of quad-channel Kingston HyperX Genesis 1600MHz memory. We're using a 240 GB Corsair Force GT SSD. The graphics card is an EVGA nVidia GTX 470. We could have gone a little more extreme on the graphics card, but our primary focus is on the CPU. To power this rig we've got an Antec High Current Gamer M 620 watt power supply.
Benchmarking Software
SiSoft Sandra 2012
PassMark - PerformanceTest - Physics
The i7-3820 outperforms the other processors with the i7-2600k surprisingly not far behind. The overclocked i7-3820 without saying blows the others out of the water.
PassMark - PerformanceTest - SSE
The i7-3820 comes in second but falls behind the i7-2600k in our SSE benchmark. The i7-2700k is also not far behind the i7-3820. Even more interesting on this benchmark is how the i7-3820 @ 4.8 GHz does only marginally better than the i7-2600k here but note its significant jump from the standard clock speed.
PassMark - PerformanceTest - Compression
For some reason the i7-2600k does really well in the compression test with PassMark. What’s really impressive is the jump in compression you get with an overclocked i7-3820. With a processor that is so willing to be overclocked it was very easy to get some significant improvements in the benchmarking results.
PassMark - PerformanceTest - CPU Mark
Here is the overall score for the CPU Mark test. We can see that the i7-3820 manages to pull out ahead of the other processors but as you can see, the gap is not as large as what you see from 1st gen i7 to 2nd gen i7. The overclocked i7-3820 really shines.
SiSoftware - Sandra 2012 - Multi-Core Efficiency - Inter-Core Bandwidth
SiSoftware - Sandra 2021 - Multi-Core Efficiency - InterCore Latency
The i7-3820 doesn’t do as well in this benchmark. It takes the lead in Inter-Core Bandwidth, but falls behind in the Inter-Core Latency test, taking longer than any of the other three processors. However, as you might have expected the overclocked i7-3820 manages to take the cake.
SiSoftware - Sandra 2012 - Multimedia Integer Native
SiSoftware - Sandra 2012 - Multimedia Float/Double Native
Intel’s i7-2700k outperforms all the standard clocked processors in this benchmark. The i7-3820 does better with integers here, but falls behind even the i7-2600k in the Float/Double Native benchmark. As we saw with the other benchmarks the overclocked i7-3820 wins again.
Our results leave us somewhat at a crossroad. It's difficult to say definitively if the Core i7-2700k or the Core i7-3820 is a better processor. The i7-3820 is certainly less expensive than the other Sandy Bridge-E processors, but there are additional expenses to consider for any SB-E setup. The motherboards are generally more expensive and so are the coolers. If price is a concern, then you might want to turn to the i7-2700k. If you care about having an integrated GPU then you should go with the i7-2700k. If you want/need 40 PCI Express lanes then the i7-3820 is the way to go. If you want the extra memory bandwidth then you should consider the i7-3820. If you are looking for a setup that can stand the test of time (keep in mind we're talking about computers here) then the i7-3820 is probably a better choice.
If we’ve learned anything from this benchmark it is that the i7-3820 certainly leaves plenty of room for overclocking. We would like to point out that this was all accomplished with air cooling. At a maximum load over several minutes, we were averaging a CPU temperature of 64 degrees Celsius. If you’re looking for a processor to overclock then this is definitely a good choice.
We mentioned earlier that building a computer boils down to features. This processor is no exception to that rule. For the features it offers and at the price point of roughly $300 we are giving this our Editor’s Choice award. You will definitely not be disappointed with this processor. It delivers in every single way you would expect from a high end processor.