Intel Core Duo
It is the innovative Core Duo processor that is the keystone of the new mobile platform. It is based on a well-known architecture borrowed from the Dothan-core Pentium M that used to come as part of the last-generation Centrino platform throughout the entire last year. Easy to guess, the main feature of Core Duo CPUs is that the new mobile processor from Intel incorporates two execution cores, architecturally alike to the Dothan. Unlike dual-core processors for desktop PCs, the Core Duo is surely the most densely integrated processor in its class. Its cores not only reside on a single semiconductor die, but also use a single and common L2 cache. This is a significant difference from Intel’s modern Pentium D for desktop computers which is based on the Presler core. Today’s desktop CPUs from Intel not only have a separate L2 cache for each core, but physically consist of two semiconductor dies that communicate via the printed-circuit board the cores are mounted on.
Well, it’s not quite correct to draw parallels between Intel’s mobile and desktop processors. It’s not a secret that these CPU families use different architectures since early 2003: the Pentium 4 and Pentium D are based on the NetBurst architecture whereas the mobile Pentium M and its modern successor Core Duo trace their origin back to the good old Pentium III. The Pentium III architecture just proved to have a better performance-per-watt ratio which is very important not only for a notebook’s performance, but also for the battery life.
It’s not that the Core Duo is just a dual-core Pentium III, though. The architecture was improved in many ways as it was transferred into the mobile CPU family, and these improvements are all available in the Core Duo, too. Main improvements in comparison with the Pentium III are: a longer execution pipeline, improved branch prediction mechanism, micro-ops fusion, dedicated stack manager, Quad Pumped Bus, SSE2 instructions set, and special technologies for lower power consumption and heat dissipation. You can learn more about the Pentium M architecture from our artcile called Intel Pentium M 780 as Heart of Your Desktop PC, with ASUS CT-479 Adapter. Intel’s engineers also made use of the transition from the single-core Pentium M to the dual-core Core Duo to add some more improvements into the micro-architecture.
The most important of them is the so-called Intel Digital Media Burst technology. It actually means that besides SSE and SSE2 the new Core Duo supports the latest SIMD instructions set, SSE3. SSE3 came to desktop processors quite a long time ago. It first appeared in the Prescott core and CPUs with this core has been selling since early 2004. So it’s quite natural that the 13 SSE3 instructions are now quite frequently employed in various multimedia applications, for example in video codecs, as well as in today’s 3D games.
Maybe not that significant, the other changes in the execution cores of the Core Duo processor should be mentioned, too. Particularly, Intel tried to improve the processor’s FPU which had been rather weak even in the Pentium III. It hadn’t been changed in the single-core Pentium M, so Intel’s mobile CPUs couldn’t boast high performance at floating-point calculations up till now. The Core Duo’s GPU has become somewhat faster at a number of operations, yet we can’t say it is a big step forward. FPU-intensive applications are still relatively slow on systems with the new Core Duo, but you should keep it in mind that such applications – video encoding, 3D rendering, 3D games – are not very often run on notebooks.