Intel's Sandy Bridge CPU architecture is set to hit mainstream PCs by 2011 and it will be known as 2nd Generation Core. The improvements over the current mainstream Core i7 series CPUs largely relate to media processing. The graphics processor and I/O components have been integrated onto the same piece of silicon as the CPU itself, and improvements have been made to Turbo Boost and power management.
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Intel Developer Forum 2010 attendees flock around the star of the show: Sandy Bridge
Sandy Bridge uses a 32nm manufacturing process and packs in more than 1 billion transistors. It has four CPU cores, an integrated graphics controller and a system agent that includes a two-channel memory controller, a PCI Express controller (1x 16 or 2x 8 lanes), the connection to the south bridge (DMI) and a DisplayPort controller. All of these parts have been designed from scratch to be integrated on the same die rather than on separate dies in within the same package. This differs from the design of the current Core processors in which the CPU, graphics and memory controllers are in the same physical package, but located on separate pieces of silicon.
One of the benefits of having all of the CPU's components on the same die is that power sensors can rapidly change the way that power flows to and from those components, thereby lowering the overall power consumption of the chip. The graphics controller and the four CPU cores have their own variable power planes, but the system agent has a fixed, low-voltage power plane. The display agent has been taken out of the graphics controller and put into the system agent. Because of this, the graphics adapter can be put into a sleep state when all a laptop is doing is displaying images from a frame buffer onto a screen. In previous designs where the display agent was located in the graphics controller, the graphics controller could not be powered down in such a scenario.
2nd Generation Core Processor, block diagram.
A key feature of Sandy Bridge is a ring connection architecture that allows the integrated graphics processor to access the same last level cache (LLC) as the four cores of the CPU. The graphics processor can put regularly accessed data into the cache in a bid to increase bandwidth (by up to four times) and also to reduce the latency that is inherent when storing data in external DRAM instead. By finding data in the LLC and not having to constantly access DRAM, overall power consumption can be reduced.
Turbo Boost can provide more headroom than it does in the current Core generation. When required, the CPU can produce a burst of speed that is above the thermal design power (TDP) specification of the CPU, but only for 10-20 seconds. It's designed to give a short, instantaneous power boost when launching applications, for example, and then it tempers back to a regular Turbo Boost speed. The extra Turbo Boost kicks in after algorithms have determined the capability of the CPU, the platform's power delivery specifications, operating system performance requests and the current workload that's running. The CPU frequency will not be unnecessarily raised if the algorithm determines that a particular action won't yield a boost in performance.
Up to a dozen new 256-bit extensions in the 2nd Generation Core Processor are present to accelerate tasks such as photo editing and video processing. The new AVX 1.0 (Advanced Vector Extensions) are claimed to deliver over the twice the performance of current generation Core i7 products using SSE 4.2 extensions.
Full specifications and platform features were not disclosed but the message is clear: the 2nd Generation Core Processor is designed to be faster at performing media tasks while at the same time cutting down on power consumption.
Elias Plastiras flew to San Francisco as a guest of Intel.