Although the Sandy Bridge CPU microarchitecture has been available in laptops and desktops for over a year, it hadn't yet made its way into the upper reaches of the computing ecosystem—until now. Intel has just introduced a range of Xeon processors intended for dual-socket servers and workstations, dubbed the E5-2600 series.
The silicon behind these new Xeons is a chip known as Sandy Bridge-EP. We've seen some of the potential of this chip in single-socket high-end desktop systems, where it has been shipping as a Core i7 for a while now. However, we haven't seen the full extent of its capabilities in that application.
Sandy Bridge-EP builds on the same exact CPU core microarchitecture used in lesser Sandy Bridge chips, where its per-core prowess has been well established. This microarchitecture achieves substantially higher per-thread performance than Intel's prior-generation Westmere processors, while adding support for new AVX instructions that double the width of vectors for floating-point math.
Content with the performance of the individual cores, Sandy Bridge-EPs architects have focused their efforts on integration of various sorts—of eight cores together, of smart power management policies, and of a staggering amount of on-chip I/O. This integration work promises huge benefits in performance, power efficiency, and system throughput compared to the last generation of Xeons based on Westmere-EP. The per-socket specs speak for themselves: 20MB of last-level cache, quad channels of DDR3 memory with transfer rates up to 1600 MT/s, dual QPI links, and 40 lanes of third-generation PCI Express connectivity—and all of those numbers double in a two-socket system.
Additionally, Sandy Bridge-EP has some impressive new features made possible by the increasing integration of various system components into the CPU silicon. For instance, the data-direct I/O feature allows data packets coming in from, say, a PCIe network interface to be deposited directly into the CPU's L3 cache for processing, saving the overhead and power consumption associated with storing the data in main memory. Also, a revamped version of Intel's Turbo Boost dynamic clocking scheme provides higher frequencies and longer residency at those higher clock rates.
All of this bandwidth and the I/O integration will, of course, require a break in socket compatibility. The E5-2600-series Xeons drop into a new LGA2011 socket that is part of a whole new platform, code-named Romley-EP. We expect every major server vendor—well, except perhaps SeaMicro—to introduce new products based on this platform very soon.
Here is a quick look at the various models of new Xeons, complete with Intel's expected pricing.
As you can see, Intel has unveiled a pretty full lineup of products at various speeds and power envelopes.
The server flagship is the Xeon E5-2690, an eight-core part with a 2.9GHz base clock, a 3.8GHz Turbo peak with only one core occupied, and a 3.3GHz Turbo speed with all cores busy. The E5-2690's 135W TDP is actually 5W higher than that of the corresponding Westmere-EP Xeons. Another model, the E5-2687W, pushes even further, into 150W TDP territory, which it can get away with because it's a workstation-only product. That additional headroom allows the E5-2687W to run at 3.4GHz with all eight cores engaged.
We'd expect the E5-2660 to be one of the most popular new Xeons, since it's the fastest model that squeezes into a 95W power envelope. With eight cores at between 2.2 and 3GHz, the 2660 should make for a nice power-performance compromise. Interestingly, so far, Intel has only two low-power variants of Sandy Bridge-EP on offer. The lowest-power option is the 2630L, with a 2GHz base clock, six cores, and a 60W TDP.
Damage Labs has been humming along rather noisily in the past couple of weeks as I've been preparing a full review of these new Xeons, including several of the models highlighted above. The initial performance results look quite striking, but there's work left to be done before I can share a fully-baked version of them with you. In the interim, I'll let slip one quick set of preliminary, experimental results. In our latest round of SPECjbb2005 tests with a new JVM, the Westmere-EP-based Xeon X5680 scores about 880K bops. The Xeon E5-2690, meanwhile, scores roughly 1.4 million bops. That's quite a nice improvement from one generation to the next, I'd say. Stay tuned for a full review.