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There’s no disputing that the 45 nm-based Core i7 is by far today’s performance leader in the consumer processor world. For raw horsepower, nothing else comes close. But in the mainstream, that $100 to $200+ price band is critical, and it left Intel with a challenge: How could the company leverage the technical advances of Core i7 and bring them into the mainstream at the price levels needed by the bulk of desktop buyers in both homes and businesses? With the new Core i3-5xx and i5-6xx series, based on a fresh 32 nm desktop architecture, we have answers.
There are several key elements that make these new Core i3 and i5 chips so compelling, many of which you’ll recognize from the Core i7, including Hyper-Threading and Turbo Boost. We’ll deal with these two shortly, but for now let’s look at two innovations unique to these new chips: the 32 nm fab process and a breakthrough shift in integrated graphics design.
Intel’s latest batch of mainstream Core i5 and i3 processors, based on a new 32 nm architecture, integrate both CPU and GPU dies onto a single chip.
Intel’s new architecture takes the 45nm architecture of last year’s Core i7, gives it a shrink to 32 nm, and scales down to a dual-core design. The proof is in the performance. The Core i5-650 easily blows past the prior dual-core flagship, the Core 2 E8400, and even the quad-core Q8400. Small design is great when it makes leaps in efficiency.
Performance aside, you see this efficiency jump clearly in power consumption. All but one of the new 32 nm desktop chips feature a 73W TDP—a massive power savings compared to 100W to 120W or higher competitors in this price range. (Only Intel’s Core i5-661 specs at 87W.) This is possible because smaller features on the die require less power, and it’s also why Intel was able to retain so much cache on the new dies. Each of these Core i5-6xx and Core i3-5xx processors has 32KB of L1 and 256KB of L2 cache per core. There’s also 4MB of L3 shared between the two cores. The cache hierarchy that was so key in last year’s Core i7 breakthroughs carries on here.
Integration marches on. With many of the old northbridge’s functions now moved into the CPU, the “chipset” has been reduced into a single chip called the Platform Controller Hub (PCH).
However, the 32 nm leap gives us something never seen before: a graphics engine built right onto the CPU in a multi-chip module (MCM) fashion. You have the 32 nm CPU die sitting right next to a 45 nm GPU die, and the two are joined by a dedicated bus. We’ve seen Intel take this MCM approach before with the very successful Core 2 Quad line, which placed two dual-core dies on a single chip.
Intel is calling this integrated GPU “Intel HD Graphics,” and it descends straight from recent GMA cores, particularly the GMA 4500 seen in the 4-Series northbridges. HD Graphics supports Shader Model 4.0, DirectX 10, and OpenGL 2.1. The two big feature advantages over the GMA 4500 are that HD Graphics now carries 12 execution units rather than 10 and the core now offers full support for MPEG-2, VC-1, and AVC hardware acceleration. Tack on the ability to share up to 1.7GB of system memory and clock speeds that run from 733 MHz on the Core i3-5xx up to 900 MHz on the Core i5-661 (hence the higher TDP). Now figure in the much lower latencies that come from having the CPU and GPU on the same chip, not communicating across a long bus from CPU to chipset.
The result of these advances is an Intel integrated graphics core that can handle true HD video (as in Blu-ray quality) without stuttering or slaughtering system performance. As the same time, the HD Graphics core can tackle a greater diversity of 3D games than any GMA processor before it. In fact, expect to see anywhere from a 40% to 80% performance boost with HD Graphics compared to the GMA X4500HD core in 3D gaming. Mind you, don’t expect miracles. You won’t see 30 frames per second at 1920x1280 with Ultra settings. In fact, to approach playable frame rates on a title like The Sims 2 or 3, users will probably need to be in 1024x768 at Low settings. But for the host of 3D online games now exploding in popularity—so-called “casual games”—the HD Graphics engine is plenty ready.
For those who admire chip design, here’s a diagram view of the inner workings within Intel’s HD Graphics engine.
Of course, the final benefit of these new 32 nm solutions is that the end-user is getting a lot more performance for less money. Motherboards based on these latest mainstream processors still deliver dual-display output for increased productivity. The low energy profile means that the Core i5-6xx and Core i3-5xx will enable cooler, smaller systems at higher speeds than prior Core 2 options. Better yet, HD Graphics wipes away the need for a low-end discrete graphics card so total system costs become more accessible. All of this adds up to a compelling foundation for business desktop systems as well as secondary PCs for students and home users, including in home theater settings.
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