Inside Intel's Santa Rosa platform

At the heart of Intel's new mobile platform is the processor, chipset and wireless combination codenamed Santa Rosa. Business notebooks built on the Santa Rosa platform will be branded Centrino Pro, while consumer systems will carry the existing Centrino Duo branding. Intel has upgraded all three platform elements, in its continuing efforts to increase notebook performance while reducing power consumption. However, not all of the components are very different to their previous versions.

Processor

The processor has changed the least. It's a 65nm Merom-based Core 2 Duo with a few tweaks, and will be the last of these CPUs before the arrival of 45nm Penryn processors in the next update. The major change between Santa Rosa's processor and its predecessors is the acceleration of the frontside bus (FSB) from 667MHz to 800MHz , together with the ability to slow it down during light loads. This technology, called Super Low Frequency Mode, knocks the bus speed down to 400MHz, the CPU's clock speed to 600MHz and reduces the core voltage. Another tweak, called Enhanced Deeper Sleep, means that the memory controller in the chipset won't wake up the processor to check on cache status if the system knows the cache is empty and the CPU is sufficiently comatose not to be able to change things.

A rather unusual performance boost comes in the form of Enhanced Dynamic Acceleration Technology. The Santa Rosa processor can run one of its two cores at full tilt while the other is in one of a number of sleep states, at which time the total thermal energy is somewhat less than the maximum allowed when both cores are running. Under conditions where only one core is running, Intel can effectively overclock it, taking advantage of the increased thermal headroom left by the other core ticking over. This will give single-threaded tasks a boost, says Intel, without risking overheating.

More performance, and lower power consumption, comes from a flash-based hard disk cache called Turbo Memory. Previously codenamed Robson, this devotes 512MB or 1GB of NAND flash memory to holding system files and other data that the operating system requires at start-up, restoring from sleep or during application switches. Intel claims that with a suitable operating system — and Windows Vista is designed for this — Turbo Memory can more than halve application load and wake-from-sleep times, while adding up to twenty minutes to battery life. Like any cache, its performance can vary according to how it's used, the mixture of reads and writes and the nature of the data sets it handles. However, with luck and application, the advantages will increase as programmers learn how to write optimal code and as flash memory gets bigger and better.

Chipset

The chipset, codenamed Crestline and officially called the Mobile Intel 965 Express, includes a wide variety of enhancements to existing power-saving techniques plus some novel ideas, especially in display management. The Display Power Saving Technology (DPST) has been improved for better colour performance; this spots display contents that are primarily dark and lightens the pixels while dimming the backlight. Display Refresh Rate Switching and interlace support reduces LCD panel performance when the system is running on batteries and when display content allows it. Other systems turn off or reduce the speed of the LAN and various peripheral connections when operating conditions permit. The whole combination can save between two and three watts of power, which results in around five to ten percent extra battery life. The graphics themselves are provided by the GMA X3100 graphics core, which has eight 32-bit floating-point execution units clocked at 667MHz, hardware shading and support for Vista's Aero graphics. However, the GMA X3100 doesn't support DirectX 10 yet.

Another new feature in the chipset is support for Intel's Active Management Technology (AMT). This has been part of the vPro business platform for a while, but has been updated for Santa Rosa. This out-of-band management support is in effect an entire separate computer with its own connection to the network, with the ability to operate even when the main processor isn't running. By giving support software access to system components when the system as a whole has crashed or is otherwise engaged, AMT helps remote diagnostic and repair efforts. The Santa Rosa version of AMT, 2.5, has the ability to use wireless networking for the first time, although limitations in how public networks are configured mean you won't necessarily be able to get IT support to fix your notebook when you're out in the field with a blue screen of death.

To qualify for the new business-focused Centrino Pro branding, a system must include Intel's AMT 2.5 firmware and an AMT/VT-capable BIOS, in addition to the other Santa Rosa platform elements. Consumer notebooks, which don't require these manageability features, will continue to be branded as Centrino Duo.

Wireless

The wireless network card in Santa Rosa, codenamed Kedron but now dubbed the Wireless WiFi Link 4965AGN, includes Intel's take on the long-delayed 802.11n standard. You can expect throughput of between 200Mbps and 300Mbps — with the appropriate wireless system on the other end, of course — but as for long-term compatibility with the finished standard, interoperability with other Draft-N systems, power consumption issues and mutual interference with 802.11b and g users within range, only time will tell.

Pricing

Prices vary from $209 for the T7100 processor with 2MB of cache and 1.8GHz clock speed to $530 for the 2.4GHz 4MB T7700. The Mobile Intel 965 Express chipset is $39 or $43, depending on configuration; the Wireless WiFi Link 4965AGN costs $29; and Turbo Memory ranges from $13 to $21, according to whether the manufacturer buys the components or the complete module, and whether they plump for 512MB or 1GB. All of these prices are for 1,000-unit deals (see the following page for the full pricing details).

Roadmap

There's a planned refresh to Santa Rosa due in the first half of 2008, which will see the introduction of a Penryn-based 45nm processor followed by a complete new Centrino platform codenamed Montevina. This will include the Cantiga chipset, WiMAX and Wi-Fi wireless (Echo Peak), a gigabit LAN interface (Boaz) and the next generation of Turbo Memory (Robson 2.0). Details on Montevina remain sketchy, but the Penryn architecture will include yet further ways to drop the processor into still deeper sleep states on the most abstemious trickle of power.

Santa Rosa: SKUs and pricing

¹  Discrete graphics including ICH8-M
²  Integrated graphics including ICH8-M
³  512MB component kit
⁴  512MB module or 1GB component kit
⁵  1GB module