Intel Arrandale: 32nm for Notebooks, Core i5 540M Reviewedby Anand Lal Shimpi on January 4, 2010 12:00 AM EST
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Clarkdale is the desktop processor, but Arrandale is strictly for my notebooks. The architecture is the same as Clarkdale. You've got a 32nm Westmere core and a 45nm chipset on the same package:
The two-chip solution does matter more for notebooks as it means that motherboards can shrink. Previously this feature was only available to OEMs who went with NVIDIA's ION platform (or GeForce 9400M as it was once known). This is the first incarnation of Intel's 32nm process so it's not quite as power optimized as we'd like. The first mainstream Arrandale CPUs are 35W TDP, compared to the 25W TDP of most thin and light notebooks based on mobile Core 2. Granted the 35W includes the graphics, but it's not always going to be lower total power consumption (more on this later).
The Arrandale lineup launching today is huge. Intel launched 7 Clarkdale CPUs, but we've got a 11 mobile Arrandale CPUs coming out today:
The architecture is similar to Clarkdale. You get private 256KB L2s (one per core) and a unified L3 cache for the CPU. The L3 is only 3MB (like the Pentium G9650) on the Core i5 and Core i3 processors, but it's 4MB (like the desktop Core i5/i3) on the mobile Core i7. Confused yet? I'll have to admit, Intel somehow took a potentially simple naming scheme and made it unnecessarily complex. We also get some low-voltage parts that have 18W TDPs. They run at low default clock speeds but can turbo up pretty high.
Turbo is hugely important here. While Clarkdale's Turbo isn't exactly useful, the TDPs are low enough in mobile that you can really ramp up clock speed if you aren't limited by cooling. Presumably this will allow you to have ultra high performance plugged-in modes where your CPU (and fans) can ramp up as high as possible to get great performance out of your notebook. Add an SSD and the difference between a desktop and a notebook just got even smaller.
Arrandale does have one trick that Clarkdale does not: graphics turbo.
GPU bound applications (e.g. games) can force the CPU part of Arrandale into a low power state, and the GPU can use the added thermal headroom to increase its clock speed. This is a mobile only feature but it's the start of what will ultimately be the answer to achieving a balanced system. Just gotta get those Larrabee cores on-die...
Chipsets are even more complicated on the mobile side: