|Intel Core i7-3820 Extreme Edition CPU|
|Reviews - Featured Reviews: Processors|
|Written by Hank Tolman|
|Monday, 05 March 2012|
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Sandy Bridge Extreme Architecture
In reality, the i7-3820 is very similar in build to the i7-2700K. The cores are nearly identical. The following is a list of the main differences between the two CPUs:
So Sandy Bridge-E does away with the iGPU. What does that mean exactly? Well, not a whole lot for most gamers and enthusiasts. The 3000 series Intel HD Graphics were good enough to play most games, but certainly not as high quality. The only real advantage of the iGPU is Quick Sync. With a Z68 motherboard, you could use your discrete GPU to power games and graphics and still use the Intel HD Graphics to transcode video as insane speeds. I'll give it up, however, for 22 more PCI-E lanes off the CPU. With only 16 lanes on LGA-1155 systems, even only a dual-GPU system lost efficiency. You had to run at two GPUs at x8/x8. With the Sandy Bridge-E platform, you can run both at x16 and even still run a third at x8. In fact, even in a four-GPU setup, your first GPU is still running at full bandwidth.
Full bandwidth brings me to another feature of the Sandy Bridge-E architecture. The PCIe lanes are actually PCIe 3.0 lanes rather than PCIe 2.0 lanes. That means that the available bandwidth is technically twice that of each of the lanes on a LGA-1155 system. So speaking from a bandwidth perspective, you are looking at the equivalent of 80 PCIe 2.0 lanes compared to just 16 on the LGA-1155 platform. Of course, we don't have GPUs or other peripherals that are built to PCIe 3.0 standards yet, but even running those last GPUs at x8, the bandwidth capability is equivalent to running at x16 on PCIe 2.0 lanes.
Above is an image depicting the die layout for the 6-core LGA-2011 CPUs. The i7-3820 obviously only has 4-cores and a smaller cache, but the concept is the same. I just wanted to point out those two areas below the three cores on either side sure look about the same size as a CPU core. This die layout can certainly support another two cores.
The X79 chipset block diagram above looks very similar to the Z68 diagram, with the differences we have already talked about, of course. Also missing is the Intel Smart Response Technology support. That's unfortunate, since SSD caching has become a much more distinct possibility with falling SSD prices. Fortunately, motherboard manufacturers are starting to implement their own solutions to this dilemma.The USB ports and SATA ports are identical to the Z68 and P67 chipsets. By that I mean no native SuperSpeed USB 3.0 ports and only two SATA 6Gb/s ports. The lack of USB 3.0 is unsurprising, but it looks like we are still going to be kept waiting for the Light Peak (Thunderbolt) Intel alternative, as it's not here on the X79 chipset. That's disappointing, but not too terrible, as I am sure almost every X79 motherboard will come equipped with an alternative controller for USB 3.0 ports. Hopefully they also come with a controller for more SATA 6Gb/s ports, as those devices are becoming commonplace.