It's always interesting to get hands-on time with unreleased hardware. We were recently able to benchmark Intel's upcoming Core i7-3960X CPU, comparing it to Core i7-990X, Core i7-2600K, and AMD's Phenom II X6. Will you be in line for Sandy Bridge-E?
There was a lot to like about Intel’s Sandy Bridge launch earlier this year. Single-threaded performance increased significantly at any given frequency. Quick Sync demonstrated commanding dominance over GPU-based transcoding from AMD and Nvidia. And, although I wasn’t over-enthused about paying extra for a K-series SKU, a mature 32 nm process easily facilitated clock rates approaching 5 GHz on air cooling.
Combined, all of those attributes took the spotlight off of Intel’s old (but still flagship) LGA 1366 interface. Even the subsequent Core i7-990X refresh, which threw six cores and a higher clock rate into the ring, wasn’t able to outperform the Core i7-2600K in enough test scenarios to warrant its $1000 price tag. The very fastest (and most expensive) Sandy Bridge-based chip could satisfy 95% of enthusiasts at less than half of the cost.
The Gulftown design’s real redeeming quality was its core count advantage, which shone most brightly in well-threaded workstation apps. But really, that was pretty much it. We even went to great lengths to show the X58’s 36 lanes of PCI Express 2.0 weren’t a real advantage over Sandy Bridge’s 16 lanes in multi-GPU configurations through an exhaustive three-part series.
There was a lot to like about Intel’s Sandy Bridge launch earlier this year. Single-threaded performance increased significantly at any given frequency. Quick Sync demonstrated commanding dominance over GPU-based transcoding from AMD and Nvidia. And, although I wasn’t over-enthused about paying extra for a K-series SKU, a mature 32 nm process easily facilitated clock rates approaching 5 GHz on air cooling.
Combined, all of those attributes took the spotlight off of Intel’s old (but still flagship) LGA 1366 interface. Even the subsequent Core i7-990X refresh, which threw six cores and a higher clock rate into the ring, wasn’t able to outperform the Core i7-2600K in enough test scenarios to warrant its $1000 price tag. The very fastest (and most expensive) Sandy Bridge-based chip could satisfy 95% of enthusiasts at less than half of the cost.
The Gulftown design’s real redeeming quality was its core count advantage, which shone most brightly in well-threaded workstation apps. But really, that was pretty much it. We even went to great lengths to show the X58’s 36 lanes of PCI Express 2.0 weren’t a real advantage over Sandy Bridge’s 16 lanes in multi-GPU configurations through an exhaustive three-part series.
At the end of the day, we had to scratch our heads and wonder how many folks would be willing to spend almost $700 more on Core i7-990X when Core i7-2600K was already so fast, and priced at $315.
But what if it was possible to cram what originally made Gulftown sexy into the Sandy Bridge mold? That’s exactly the premise behind Sandy Bridge-E, set to become the next enthusiast-oriented platform, replacing Gulftown and its LGA 1366 infrastructure.
More important than what Sandy Bridge-E is going to do on the desktop is what it’ll become in the server space. Truly, this is a design destined to drive Intel’s Xeon E5 family, comprised of 1P-, 2P-, and 4P-capable parts.
A Naming Convention, Revised
For the time being, Sandy Bridge-E is expected to reach enthusiasts in three different trims: the Core i7-3960X, the Core i7-3930K, and the Core i7-3820.
| Second-Gen Core i7 Processor Family | |||||||
|---|---|---|---|---|---|---|---|
| Processor | Base Clock | Max. Turbo Clock | Cores / Threads | L3 Cache | Memory | Interface | TDP |
| Core i7-3960X *Unlocked | 3.3 GHz | 3.9 GHz | 6/12 | 15 MB | 4-channel DDR3-1600 | LGA 2011 | 130 W |
| Core i7-3930K *Unlocked | 3.2 GHz | 3.8 GHz | 6/12 | 12 MB | 4-channel DDR3-1600 | LGA 2011 | 130 W |
| Core i7-3820 *Partially Unlocked | 3.6 GHz | 3.9 GHz | 4/8 | 10 MB | 4-channel DDR3-1600 | LGA 2011 | 130 W |
| Core i7-2600K *Unlocked | 3.4 GHz | 3.8 GHz | 4/8 | 8 MB | 2-channel DDR3-1333 | LGA 1155 | 95 W |
| Core i7-2600 | 3.4 GHz | 3.8 GHz | 4/8 | 8 MB | 2-channel DDR3-1333 | LGA 1155 | 95 W |
| Core i7-2600S | 2.8 GHz | 3.8 GHz | 4/8 | 8 MB | 2-channel DDR3-1333 | LGA 1155 | 95 W |
For instance, the flagship Core i7-3960X should ship with a 3.3 GHz base clock that spins up to 3.9 GHz with one or two cores active. It’s slated to include six cores, Hyper-Threading-capable, meaning it's equipped to handle 12 threads simultaneously. Core i7-3930K will step down to 3.2 GHz with a maximum Turbo Boost frequency of 3.8 GHz. And the Core i7-3820 is expected to feature a more aggressive 3.6 GHz base clock able to reach 3.9 GHz with Turbo Boost. It’ll only sport a 4C/8T arrangement, though.
Sandy Bridge-E carries over the per-core 32 KB L1 data/instruction and 256 KB L2 caches. The shared last-level cache is a bit different, though. Sandy Bridge employed one 2 MB slice of L3 cache per core, totaling 8 MB at most. This is seemingly increased to 2.5 MB per core and still granular down to 512 KB, enabling the 12 and 10 MB caches expected from the -3930K and 3820, respectively.
Nehalem’s triple-channel DDR3-1066 memory controller gives way to a quadruple-channel controller able to support DDR3-1600 data rates. The potential increase in memory bandwidth, from 25.6 GB/s to 51.2 GB/s, is massive. But don’t expect to see a corresponding increase in benchmark performance on the desktop. As it was, the Nehalem architecture was not bandwidth-starved on X58 (we even proved it in Core i7 Memory Scaling: From DDR3-800 to DDR3-1600). And Sandy Bridge has no problem flying right past Bloomfield with only a dual-channel DDR3-1333 memory controller.
http://www.tomshardware.com
