Under The Hood: Sandy Bridge-E Benchmarked

Under The Hood: Sandy Bridge-E Benchmarked

Intel’s new Sandy Bridge-E chip reigns supreme — and we have the charts to prove it. True performance enthusiasts have had a very difficult choice this past year. Go for maximum core and thread count using an older core microarchitecture, or cheap out and get almost the same (or better) performance in most apps and games using the mainstream Sandy Bridge chip.

That, in a nutshell, has been the enthusiasts’ dilemma ever since Intel introduced the Sandy Bridge chip in January 2011. Well those days are behind us now that Intel has finally, finally released its Sandy Bridge-E (for Enthusiast) chip. With one simple chip-the new 3.3GHz Core i7-3960X-Intel has neatly folded up all those worries and put them into a nice little blue box stamped with the Intel logo.


Boiled down to the simplest of terms, if the quad-core 3.4GHz Core i7-2600K (or its new sibling the 3.5GHz Core i7-2700K) was the best chip out there, the Core i7-3960X is now the bestest. That’s because the Core i7-3960X is simply a Core i7-2600K with two additional cores.

Actually, that’s not really accurate. As an enthusiast chip, there are no graphics cores in the Core i7-3960X. And while the Core i7-2600K is limited to just 16 PCIe 2.0 lanes, the Core i7-3960X sports 40. Even better, those 40 lanes of PCIe support are PCIe 3.0 compliant. Out the gate, however, Intel (or its lawyers, anyway) is reluctant to label them as PCIe 3.0 until it actually has enough PCIe 3.0 cards to test.

Under The Hood: Sandy Bridge-E Benchmarked

Intel’s Sandy Bridge-E blends the best of both worlds: it has the core and thread count of a Core i7-990X Gulftown proc and the core performance of a Core i7-2600K Sandy Bridge.

As to the cores, you already know about them. They’re Sandy Bridge cores and include AVX and AES-NI instruction-set goodness. Turbo Boost 2.0 on these models will take the top-end 3.3GHz Core i7-3960X to 3.9GHz. The cores are built using Intel’s 32nm process and, well, there are two more of them turned on.

Besides the added cores, enthusiasts will also be thrilled by the memory support: To keep those cores fed, Intel is using a new quad-channel memory controller. The memory controller seems significantly faster than previous iterations too. While the tri-channel memory controller in the original LGA1366 didn’t blow our socks off (over a dual-channel configuration), the quad-channel controller in the Core i7-3960X has us stunned. In our tests, we found that it offered nearly 100 per cent more memory bandwidth than the Core i7-990X’s triple-channel configuration.


Intel isn’t making the Core i7-3960X just to satiate the appetites of speed freaks. The chip is mostly intended to be sold as a Xeon workstation CPU. So it shouldn’t surprise you that the Core i7-3960X is actually an eight-core chip. Yup, that’s right; looking at the block map of the chip, you can see that the new CPU has two sections blocked out where cores seven and eight go. Why leave them off? Intel officially says the decision was based on its desire to balance clock speeds, thermals and power needs. We suspect that it’s really because Intel doesn’t need those two extra cores at this point. Not to telegraph too much, but AMD hasn’t posed much performance competition yet. By leaving cores off now, Intel can always introduce octo-core chips later if it needs to be more competitive. There could also truly be a thermal concern, as unsubstantiated rumours (are there any other kind?) initially told of Intel’s new chip pushing an unheard‑of 180‑watt thermal rating.

Yeah, we know what you’re thinking already, because we asked the same thing ourselves: Can you unlock those two other cores? Negative, Ghostrider. Intel has laser-cut those cores off in the die, so unless someone has the smallest‑possible soldering gun, we’d bet a box of adamantium claws that it’s impossible.



Don’t rub your eyes: There really are eight cores on that monstrous 32nm die. And no, you can’t unlock the bottom two, except in your wildest dreams.

As is Intel’s modus operandi, the company has a new socket. While the switch from LGA1156 to LGA1155 certainly pissed off customers, the LGA1366 crowd can hardly complain. LGA1366 launched with the original Core i7-965 Extreme Edition way back in 2008. For Intel to even support a socket that long is almost unheard of. So, with Core i7-3960X, Intel is introducing its new LGA2011.

Why the extra pins? The additional pins in the socket are to support the quad-channel memory and the relocation of the PCIe lanes from the core-logic chipset to the CPU core (à la Sandy Bridge and Lynnfield). For the most part, enthusiasts will be tickled pink with the beastly new socket, the quad-channel memory, and PCIe 3.0. What they won’t be happy with is the SATA 6Gb/s situation. The new X79 chipset features a Serial Attached SCSI controller that can support up to 10 drives in SATA 6Gb/s, but at the 11th hour, the feature was switched off due to compatibility concerns. Instead, we’re left with an X79 peripheral controller hub that’s pretty much a weak-sauce retread of the P67 and Z68’s PCH: two SATA 6Gb/s and four SATA 3Gb/s ports. You can certainly argue that you don’t need more than two SATA 6Gb/s ports since they’re only useful for SSD drives, but we think it stinks, especially as we had been teased by thoughts of motherboards bursting with SATA 6Gb/s. We expect initial boards to be limited in SATA 6Gb/s ports due to the last-minute switch, but in a few months, board vendors will tack on additional ports using third-party controllers. If anything, the SATA 6Gb/s features on boards and how they’re implemented will separate the men from the boys in mobo land.


For the LGA2011 platform, Intel is introducing three new chips: The top-end Core 7-3960X at $US990-yup, that’s $US9 cheaper than the existing Core i7-990X chip (gee, thanks Intel!) that this Extreme chip is meant to replace. Intel is also introducing two other chips. The mid-tier 3.2GHz Core i7-3930K will sell for $US555. Besides the lower stock clock, the chip will shed some of the L3 cache, for a total of 12MB. For the budget enthusiast, Intel has plans to release a quad-core, Hyper-Threaded Sandy Bridge-E with 10MB of L3 cache early next year. Prices of the Core i7-3820 haven’t been released, but we’re pretty sure it’ll slot in at about $US300. The part is “partially unlocked”, meaning it will have limited overclocking features, and is likely intended as a way to get entry-level enthusiasts in the X79 game.

The good news for enthusiasts is that Intel has no plans to step away from offering blistering‑fast chips with cutting-edge technology, despite all the focus on tablets and smartphones these days. Hallelujah.

Under The Hood: Sandy Bridge-E Benchmarked

Application Benchmarks


Under The Hood: Sandy Bridge-E Benchmarked

3DMark11 is considered a GPU test but its overall score is actually created from “the graphics score, Physics score, and the Combined score using a weighted harmonic mean”. That basically means it’s still a test that is weighted heavily towards graphics performance. For our test, remember, that we used identical GeForce GTX 580 cards all running the same graphics drivers. In the end, the new Sandy Bridge E part was the fastest, but really, we’re not talking by a huge margin because 3DMark11’s overall score is so heavily weighted toward the GPU in the slot-not the GPU in the socket. For this run, we run the default standard test which is Performance. Higher is better here.

Under The Hood: Sandy Bridge-E Benchmarked

3DMark11’s physics score for the new Sandy Bridge E shows just how heavily weighted it is toward the GPU. The 3DMark11’s Physics test “focuses on CPU performance by simulating rigid body physics with a large number of objects. This test runs at a fixed screen resolution for all presets. There is no post processing, volumetric lighting, or tessellation.”

Here, Sandy Bridge E simply crushes the competition to dust even smashing its cousin the Core i7-990X to tiny bits which surprised us as both chips have the same core and thread counts. It’s quite possible the insane amounts of bandwidth available to the Sandy Bridge E chip accounts for some of this, or its crazy arse big cache. When we get a chance, we’ll switch the X79 to dual-channel mode and rerun the test. For now though, Sandy Bridge E stands tall. Higher is better here.


Under The Hood: Sandy Bridge-E Benchmarked

For our Handbrake test, we used a video file shot with a Canon EOS 5D Mk II at 30fps (the 24fps firmware wasn’t available at the time) and tasked Handbrake with encoding it to H.264 using the high profile setting. Handbrake is a widely used free encoder that favours using the CPU for encoding due to the consistent quality over GPU encodes. The Core i7-3960X again leads the pack by an impressive healthy margin over the six-core Core i7-990X chip. The eight-core FX-8150 also holds up its head when compared to the Core i7-2600K chip. We say this despite the Core i7-2600K being a four-core chip with Hyper-Threading because of the pricing of the lower pricing of the FX-8150.


Under The Hood: Sandy Bridge-E Benchmarked

PCMark7 is the latest in FutureMark’s popular all-around performance tests. It’s not designed to test just the CPU as it factors in storage and graphics into its score, too. The overall score is based on storage performance tests in Windows Defender, importing pictures, gaming as well as video playback and transcoding performance, image manipulation, web browsing and decrypting. Since we use the same hard drives and GPUs in our tests, the graphics performance and storage components should be mostly even. The differences you see here should mostly be the result of image manipulation, web browsing, and decrypting and video transcoding here. The Core i7-3960X just edges the Core i7-2600K and yields an advantage over the Core i7-990X. We’ve read reports that the test is multi-threaded but we suspect it tops out with but four cores. Again, the score is heavily weighted by storage subsystems. Since we used the same Raptors across the board, our scores are significantly lower than those using an SSD.

For even more benchmarking and conclusions, head to MaximumPC.