Introduction
With the launch of the Core 2 Duo and Core 2 Extreme, Intel has become the proud parents of a brand new bouncing baby processor family. The launch date was July 27 (2K6).
To say that this was a highly anticipated launch is an understatement. Intel has alot of design wins, "the most in Intel's history".
Core Microarchitecture
The Core 2 processor family is based on the Core microarchitecture, which covers servers (Xeon 5100 series), desktops and notebooks (Core 2 Duo & Core 2 Extreme).
The earmarks of the Core microarchitecture are high performance, on the one hand, and energy efficiency, on the other.
The Core microarchitecture strives to do more work in less time.
Wide Dynamic Execution
One of the ways that Core accomplishes more in less time is by executing up to 4 instructions at a time, per clock cycle, whereas previous microarchitectures are able to execute at most three instructions at a time.
Advanced Digital Media Boost
Similarly, the Core microarchitecture can execute one full SSE (Streaming SIMD Extensions) instruction per clock, rather than taking more than one clock cycle to execute a SSE, like other designs.
Smart Memory Access
One of the advantages that AMD has over Intel is that AMD puts the memory controller on the CPU die, whereas with Intel the memory controller is part of the chipset. Using the northbridge of the chipset as a memory controller forces data to move along a front-side bus (FSB) on its way back and forth between the CPU and the northbridge.
The journey along the FSB increases the amount of time it takes the CPU to access data from memory, a factor known as latency, and the FSB also limits the amount of data to as much as can travel along the FSB. This is a memory bandwidth limitation.
AMD, on the other hand, is not limited in bandwidth by the FSB, because the FSB doesn't exist, and memory latencies are quite low because there is virtually no distance to travel to the memory controller, which is on the CPU die.
Intel addresses many of the shortcomings of a FSB architecture with Smart Memory Access.
Smart Memory Access makes the most of memory bandwidth traveling along the FSB. While the bandwidth of Core 2 processors is much improved over the previous generation Pentium D, this is one area in which AMD still commands a lead, thanks to its on-die memory controller.
The other issue that SMA addresses is latency. Intelligent prefetchers grab the data and have it ready for the CPU when the CPU needs it.
SMA hides the memory latency inherent in the front-side bus approach. It doesn't get rid of it. It's still there. Nevertheless, SMA works so well that Intel bests AMD on some latency benchmarks--in spite of AMD's on-die memory controller!
Active Smart Cache
The L2 cache under the Core microarchitecture is shared. This differs from the Pentium D, for instance, which has two independent, non-shared caches, one for each core. The problem is that, if data is present in one core's cache and needed by the other core, the other core takes a performance hit and has to go outside of the cache to retrieve the information.
However, not only is the L2 cache shared, it is dynamically allocated to the two cores in the most efficient manner. This way, a single core can use up to 100% of the shared cache, if the other core is idle. "Only Intel provides this capability in all segments".
New Processors
Intel uses one of its brands for both mobile and desktop chips. That would be Core 2 Duo. It's a mobile chip. It's also a desktop chip.
Even though they share the same name, the mobile chip has more technologies than the desktop chip. Most of these lie in the realm of power management.
So how is one supposed to distinguish the two chips, if they use the same name? That's simple. One is called the Core 2 Duo mobile processor, the other the Core 2 Duo desktop processor.
Intel launched 5 notebook and 5 desktop processors. That's five Core 2 Duo mobile processors, four Core 2 Duo desktop processors and one Core 2 Extreme processor.
All of these processors are or shall become important parts of Intel's platforms: Centrino, Viiv, and vPro, for notebooks, home entertainment, and business.
Not all of the technologies found in Core 2 processors are distinctive to Core 2. Some of the technologies are found in other Intel chips as well. Some of these technologies require the use of other hardware and software.
The Execute Disable Bit requires "a supporting operating system".
Both Intel's Virtualization Technology (VT) and 64-bit technology require a supporting chipset, BIOS, operating system, and other software.
Fan-speed control features require "a properly designed motherboard".
Desktop Processor Differences
All Core 2 desktop processors are overclockable. However, only the Core 2 Extreme ships with an unlocked multiplier. In Intel's words, the bus ratio locks "have been removed".
The locks, when present, exist for overspeed protection, but in the hands of someone who knows what they're doing, an unlocked multi allows for greater flexibility in overclocking.
Other differences between Core 2 Duo desktop from Core 2 Extreme are minimal.
Some of the Core 2 Duos have only 2MB of shared L2 cache. Core 2 Extreme, as well as other Core 2 Duos, have 4MB.
Core 2 Extreme is clocked a bit faster than the fastest Core 2 Duo. Big woop.
Chipset recommendations differ slightly, too.
Intel recommends one of the 965 Express Chipsets for the Core 2 Duo desktop, and either a 965 or the 975X Express Chipset for Core 2 Extreme.
A 965 Express Chipset works with a Core 2 processor to regulate fan speed depending on the temperature of the CPU. This allows for quieter running systems.
The 975X Express Chipset does not have this fan-regulating technology. The 975X instead offers support for dual graphics.
At the moment, you can have either a quieter system or dual graphics, but you can't have both.
Centrino Duo with the Core 2 Duo Processor
Intel is not calling it Centrino anymore. Rather, it's Centrino Duo with the Core 2 Duo processor.
Staggered Shipping Dates
One of the things that NVIDIA started doing was to have products fully available at the time of their launch. This is something that other chip manufacturers have tried to emulate, but have had trouble doing.
While the launch date of the Core 2 processors was July 27, Intel is going with staggered shipping dates.
Only the Core 2 Extreme was readily available at the time of launch.
The Core 2 Duo desktop processor is to become available in the first part of August, any day now, in fact.
The mobile Core 2 Duo was originally expected late August or early September. The launch of the mobile processor was moved up to coincide with the desktop launch because the two chips are so similar that there was little point in separate launches. However, the ship date for the Core 2 Duo mobile processor remains as it was, late August.
Maybe the need for a new mobile chip was not as pressing as the need for new server and desktop chips, where Intel was getting beat up on the benchmarks. At any rate, the server version of the Core microarchitecture, the Xeon 5100 series, became available in June, the desktop versions are either shipping now or soon to ship, and the mobile version is scheduled to ship late August.
Third Generation Dual-core
This is the third generation of Intel's dual-core technology, the first being the Pentium D, the second Core Duo, or Yonah, and the third being the Core 2 processor family.
It is the second generation of mobile dual-core technolgy, the first being Core Duo, aka Yonah.
The Core 2 processor family improves upon the Pentium D in two ways: performance and energy efficiency, advancing the platform by up to 40% both ways. Improvements over the previous generation mobile processor are not nearly as dramatic, though they are present.
Core 2 Duo fits inside the current Centrino Duo platform, called Napa. In fact, the current platform with a Core 2 Duo processor is known as the Napa Refresh.
The mobile version of the new processor is thus drop-in compatible with the current Centrino platform, and the platform should be easily upgradable to Core 2 Duo.
Because the Napa platform already exists, many of the neat features of the technology--support for 802.11e QoS, a 667MHz FSB--are already present. The net effect of the Core 2 Duo mobile processor is thus blunted to a nice little performance boost.
Intel 64
Intel may be changing the name of its 64-bit technology from EM64T (Enhanced Memory 64-bit Technology) to simply Intel 64. This latter name is more in line with what AMD calls their 64-bit technology, which is AMD64.
Regardless of the name, however, one of the most important changes that Core 2 Duo brings to Centrino is 64-bit computing. "64-bit computing now expands to notebook PCs".
Before, if you needed 64-bit, you had to go with an AMD mobile solution, or stick with a desktop. Now, you can have a 64-bit Intel notebook.
64-bit technology allows a system to address lots and lots of memory, say, if you need to render the fur on lots and lots of lemurs, as was needed for the film Madagascar.
64-bit computing is expected to come into its own with Windows Vista, which should also come in a 64-bit version.
Santa Rosa
Intel shall eventually issue the Core 2 Duo mobile processor with a different pin layout, which shall be incompatible with the current pin layout of Napa. Mobile Core 2 Duo shall transition from Socket M to Socket P.
More importantly, Core 2 Duo shall be paired with a different chipset, a mobile 965 chipset, codename Crestline. A new chipset means a new platform, in this case, Santa Rosa.
New wireless technologies are on tap for the new platform, including 802.11n MIMO (Multiple-input, Multiple-output) wireless Ethernet.
Robson cache is rumored to accompany the platform. Robson is nonvolatile flash memory included somewhere on the motherboard, and shall speed things up.
Expect the front-side bus (FSB) to be bumped from 667MHz to 800MHz. Sometimes progress consists of slow and steady changes.