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• The company won’t get specific about the changes made to its QuickPath Interconnect, the point-to-point interface first used to attach Core i7 to X58. But there is a QPI link inside of Lynnfield, serving as the glue between on-die PCI Express and the uncore. Intel has a lot more freedom with this technology now, since it doesn’t have to leave the die. Thus, the performance and timings are both reportedly better here than they were on Bloomfield. This interconnect is important today, naturally, but will become a key performance enabler when Clarkdale launches next year. With graphics and memory control on the same piece of silicon, memory bandwidth—one of the biggest Achilles’ heels of integrated graphics designs—is delivered much more effectively. As a result, expect to see Intel adjusting the speed of its internal QPI link up or down to differentiate its Clarkdale SKUs. Of course, none of that is really a concern with Lynnfield, which employs 16 lanes of integrated PCI Express 2.0 to interface with discrete GPUs. We’ve already spent considerable time comparing the performance of single- and dual- card configurations on P55 against X58, P45, and 790GX using 2.8 GHz processors. We've determined that there’s very little gain or loss resulting from Intel’s Lynnfield implementation. In other words, the integration of PCI Express is just about as close to transparent to end-users as possible. This is the way integration should work (though most of us have been conditioned to think it automatically leads to performance sacrifices). Much more impactful is the licensing of SLI and CrossFire, which allows most P55-based motherboards to support either technology, just like X58. Of course, the difference is that P55 platforms are going to be significantly cheaper. More on the chipset shortly. Finally, you have the processor’s integrated DDR3 memory controller, which is cut from three 64-bit channels in Bloomfield to two 64-bit channels with Lynnfield. Officially, Bloomfield is rated for up to DDR3-1066, yielding a theoretical maximum of 25.6 GB/s of bandwidth. We’ve all seen the LGA 1366-based Core i7s scale as high as DDR3-2133 though, so the official spec means very little to enthusiasts. In contrast, Lynnfield is rated for DDR3-1333 memory modules, offering up to 21.3 GB/s. For the most part, the loss of that third channel is made up for by an increase in attainable data signaling rate. We’ll put this theory to test in a couple of pages. LGA 1156: More Socket Segmentation The table below should look somewhat familiar; I used it back in February to chart the last nine years of desktop socket launches from Intel and AMD. With the debut of LGA 1156, the Intel column is looking pretty darned crowded. Disruptive Socket Launches YearAMDIntel 2001Socket 478 2002 2003Socket 754 2004Socket 939LGA 77520052006Socket AM2(Intel launches Core 2 Duo, most motherboards need to be replaced)20072008LGA 13662009(Socket AM3–new processors work in old motherboards, but not the other way around)LGA 1156 I’m sure there will be a number of enthusiasts who’ve spent a lot of money on LGA 1366, X58, and Core i7. You'll see the performance of Lynnfield, compare the cost, look at the upgrade path to Clarkdale, and ask me why I couldn’t have given a more vocal heads-up about what was to come. To those folks, let me give you one hopefully-welcome piece of information: the upcoming Gulftown design (32nm, hexa-core, Hyper-Threading-enabled) will be a drop-in upgrade to your existing platform. Meanwhile, those waiting on Clarkdale have a dual-core design to look forward to—certainly not as sexy, unless you’re really itching for integrated graphics.  What, then, was the impetus behind LGA 1156 less than a year after LGA 1366? And why couldn’t Intel integrate PCI Express on the LGA 1366 platform, too? Right from the get-go, 1366 was designed as a DP interface for Intel’s Tylersburg platform. The fact that it surfaced first on the desktop is similar to how LGA 771 made a brief appearance in Intel’s Skull Trail gaming configuration. The difference is that motherboards based on X58 made their way under $200 and the cheapest processors dropping into the interface are less than $300. That’s not little money, to be sure. But it’s affordable enough to tempt the folks who know how fast an overclocked i7 machine can be. LGA 1366 didn’t get PCI Express because it would have made the pin-out far too complex. Plus, the servers and workstations that now use the 5520 and 5500 chipsets need access to more than just 16 lanes of connectivity for storage controllers, professional graphics cards, and high-speed networking. Thus, LGA 1156 becomes the true successor to LGA 775, despite now-convoluted segmentation. It’s simpler than LGA 1366, its locking mechanism applies pressure more evenly on the CPU’s heat spreader, and it helps protect against EMI—particularly important when Clarkdale exposes on-chip graphics. You can expect this processor interface to remain pervasive until the end of 2011, when LGA 1155 (planned launch in the first half of 2011) starts grabbing market share big time.

• A processor’s power consumption can be reduced in two ways. The first way involves the use of new manufacturing processes/techniques and the second consists of special architectural features. Power Savings By Technology Intel has been able to revamp its manufacturing processes roughly every two years as it continues to successfully output denser devices. The 65 nm manufacturing process, which came online in 2005, was replaced by the 45 nm process in 2007. In 2009, Intel will likely ramp up its 32 nm process. In recent years, every new generation offered increased performance with lower power requirements both in idle and at peak loads, which compensated for how smaller transistor sizes typically increased the risk of power leakage. ProcessCode NameIntroductionMain Feature90 nmP12622003Strained silicon, copper interconnects, low-k dielectrics65 nmP126420052nd-generation strained silicon, high-k gate dielectrics45 nmP12662007Hafnium-based high-k gate dielectrics + metal gates for reduced leakage power32 nmP1268Expected 2009...22 nmP1270Expected 2011... Intel says that the transistor gate oxide leakage could be reduced tenfold, while processors produced with the 45 nm process had only one-fifth of the source-drain leakage compared to devices produced with the 65 nm process. While it’s hard to verify these statements, we can definitely confirm that the Core 2 Duo E8000’s power consumption is significantly lower than that of 65 nm E6000 series devices. Each new processor series has thus offered an increase in power efficiency. Power Saving Features: CPU C-States New features can decrease power consumption as well. The first way is to use different CPU power modes, which are referred to as C-states. While these can be applied to operating system C-states, the following table applies to an entire processor. C-StateAMDIntelTransition Time Back To C0C0*N/AC1*Halt State for main CPU clocks ~ 10 nsC1EEnhanced Halt - Stops CPU clocksEnhanced Halt - Stops CPU clocks and reduces Vcore>10 nsC2Stop Grant - Stops internal clocks via hardware, includes I/O buffers to save system Power~ 100 nsC2EN/AExtended Stop Grant - Stops CPU clocks via Hardware and reduces Vcore> 100 nsC3 Sleep: Stops all internal CPU clocksDeep Sleep: Stops all internal and external clocks.~ 50 µsC4Deeper Sleep: Reduces Cpu Voltage~ 150 µsC4E / C5Enhanced Deeper Sleep: Further reduces CPU voltage and switches off cache~ 250 µsC6Deep Power Down: Further reduces CPU VoltageCPU context not preservedUnknown * required in all modern processors Note that not all processors support all C-states, and that processors may only support some of these. Mobile processors typically support more of the higher C-states, while desktop processors are oftentimes limited to only a few C-states. Since marginal power savings are less useful on the desktop, but may be significant for laptop computers, this differentiation makes sense. There is a reason why we list all these technical details: Switching from full-power operation mode into a low-power mode takes time. Please see the right column of the table above for details. While switching from C1 or C2 back to C0 mode can be done with hardly any delay, the deeper C-states require more system parameters to be modified, hence it may take up to 250 micro seconds to go back to full-power mode. Power Saving Features: CPU P-States Then there are AMD’s Cool’n’Quiet and Intel’s SpeedStep or Enhanced SpeedStep (EIST) power savings features, with which most users are already familiar. Cool’n’Quiet and EIST are available in almost all processors that are on the market today. While the C-states only apply when the processor is in true idle mode or is requested to switch into sleep mode (e.g. when putting the system into standby), the power-saving features make use of so-called P-states (performance states), which AMD and Intel implement in a similar way today. As long as the CPU is in active mode (C0), Cool’n’Quiet or Enhanced SpeedStep may kick in. It is necessary to have BIOS and operating system support. With this requirement satisfied, Windows will trigger clock speed and voltage throttling for the processor, typically reducing AMD clock speeds to 1.0 GHz and Intel speeds to anywhere between 1.2 and 2.0 GHz, depending on the front side bus (FSB) speed. These features are crucial when it comes to reducing power for everyday applications.