The newest version of Intel’s laptop platform is here. We unveil and test real Santa Rosa hardware.
The Centrino mobile brand is one of Intel’s major success stories of the last few years, and it’s had constant updates to keep pace with technology since its introduction in 2003. This latest revision is one of the most comprehensive yet. As ever, the new Centrino – technically Centrino Duo with its dual-core processor – comprises three modules, all of which need to be present for a notebook to qualify for the official Centrino label. The three modules in question are the processor, chipset and wireless module.
New processor
The new mobile versions of the Core 2 Duo processor receive a comprehensive set of tweaks. Most novel is Intel Dynamic Acceleration. This is a workaround to get maximum performance for the large number of single-threaded applications still around that don’t benefit from dual cores. Games are among the primary guilty parties here and, with Intel’s general attempt to court more gamers and enthusiasts, it’s a canny move. Dynamic Acceleration technology works by detecting when one core is largely idle and the other is at 100% utilisation.
In this situation, it can stop the clock of one core, while boosting the speed of the other above its nominal speed rating. Ordinarily, overclocking a mobile processor is taboo, since the extra power consumption will breach the thermal design of a chassis, leading to overheating problems. But with one core stopped – and thus consuming almost no power – the other’s clock frequency can be increased while still keeping the total power consumption within the chip’s 35W TDP (thermal design power) envelope. Concrete details of the extent of the IDA speed increase haven’t been confirmed, but an Intel spokesperson told us that, essentially, the processor moves up to the next speed bin rating, so a 2.4GHz T7500 will temporarily clock itself up to 2.6GHz.
There are six new processor models. The four standard T-series offerings range from 1.8GHz to 2.6GHz, with either 2MB for the lowest-end T7100 or 4MB of Level 2 cache for the rest of the range; the maximum 4MB of Level 2 cache complement is unchanged from the previous mobile Core 2 generation. There are also two lower-power LV (low-voltage) offerings at 1.4GHz and 1.6GHz, plus some as-yet unconfirmed ULV (ultra-low voltage) variants. See the table below for more details.
The final major improvement is an increase in FSB (front side bus) speed, which rises from 667MHz to 800MHz. Maximum memory speed via the chipset is still limited to 667MHz, however, so the overall speed increase won’t be as high as a uniform boost.
Processor power management
Power management has been further refined to keep increased clock speeds from pulling the processors over their TDP ratings. As well as processor clock speed, for the first time, the FSB speed can be dropped too. More subtle refinements include a system to allow the processor to deep-sleep for longer in the existing Enhanced Deeper Sleep stop-clocked state, by letting the chipset know the processor cache has been flushed so it doesn’t need to wake it unnecessarily during “snoop” cycles.
On the chipset and supporting components side, Intel claims the total power savings across the platform for Santa Rosa can add up to over 2.5W. Almost 1W of that comes from the new but unlikely-to-be-used ability of the wired Ethernet connection to drop its speed to 100Mb/sec while running on battery. Nonetheless, that still represents a saving of over 1W, which in an average notebook can theoretically add around 20 to 30 minutes to the battery life.
Chipset changes
The old Centrino platform, codenamed Napa, was based on the Mobile 945 chipset family, which itself was a derivative of the last-but-one 945 Express desktop chipset. Centrino now moves up to the new Mobile 965 chipset, which includes the ICH8M south bridge chip for peripheral communication. The ICH8M actually provides the most interesting enhancements, with 3Gb/s SATA support and up to ten USB ports. There’s also an Enhanced version of the ICH8M to support wireless AMT (active management technology) under the newly announced Centrino Pro platform, and Intel’s Matrix Storage RAID system, which allows mixed RAID0 and RAID1 partitions on a pair of drives.
New wireless module
For home use, the increased wireless support of the new platform is likely to be the biggest tangible improvement. The complete platform will now feature the new 4965AGN wireless adapter, which is an 802.11n adapter with full MIMO (multiple-in, multiple-out) capability, with all the speed and range benefits that confers. Beware, though, you’re not automatically guaranteed 802.11n; there’s also a 4965AG adapter without N capability. Even at this stage the difference in price is, according to Intel, only US$7, so it’s unlikely there’ll be too many non-N laptops released.
New graphics adapter
Reflecting its new-found enthusiasm for luring gamers, Intel is concentrating on graphics performance for the new platform. The integrated graphics option for the new Centrino adopts the relatively advanced X3000 series GPU, previously available only in desktop 965 chipset boards and now updated to form the GMA X3100. With its hardware T&L (transform and lighting) capability, it’s a significant step up from the GMA 950 of the previous mobile generation. It falls short of DirectX 10 support, although that’s promised in a mobile chipset next year, but it does have a 500MHz core clock and 128 shader units. Intel is unlikely to be challenging NVIDIA and AMD/ATI for graphics prowess anytime soon, but our initial results aren’t too positive. That said, we’ve seen the new adapter running a convincingly fluid demo of Half-Life 2.
Turbo Memory
Previously known as Robson, Turbo Memory is a new feature of the updated Centrino platform. Much like Windows Vista’s ReadyBoost, it speeds up the system with flash memory, with a choice of 512MB or 1GB modules. In fact, it’s based on Vista’s ReadyDrive technology (and this only works in Vista). ReadyDrive acts as an extra cache for the hard disk at a low level, where ReadyBoost is used as an extra cache for main memory. The fact that ReadyDrive/Turbo Memory sits between the main system and the hard disk means it can act as an effective buffer, reducing the need to spin up the drive. That means it saves some power as well as theoretically increasing system performance. It’s a plug-in module with a PCI Express interface.
A little refreshment
Finally, Santa Rosa, like Napa before it, is due to undergo a “platform refresh” next year. The main change will be the move to a 45nm processor, based on the upcoming Penryn design due to appear in desktops in a couple of months. Also worth noting is an optional WiMAX module, although that’s fairly academic in Australia where there’s little prospect of coverage for some years yet.
Conclusion
While we’re not bowled over by this release in the same way we were when the previous-generation Core and Core 2 Duo variants hit the ground at a dead-run, Santa Rosa is an impressive bundle of technologies. We’re looking forward to seeing some production samples when the bugs are ironed out, and can’t wait until the new platform finds its way into notebooks like Sony’s G-series. When that happens, our hopes are high for record-breaking battery life.