Intel's Ivy Bridge: The Maximum PC Review

Posted 04/24/2012 at 11:24am | by Gordon Mah Ung

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The world’s smallest-process consumer CPU comes out in a big way

You are, no doubt, quite familiar with Intel’s CPU-release “cadence” of tick-tock by now. If not, the short story is that every tock brings a major breakthrough, while ticks are decent upgrades but nothing to Twitter home about.

That’s not necessarily the case with Intel’s latest tick, the Ivy Bridge CPU. Sure, the performance enhancements on the x86 side of the aisle won’t exactly knock you on your tuchus, but they’re still decent. The upgrades to the graphics core, however, make Ivy Bridge more noteworthy.

As we know, Intel found religion through graphics and has been progressively improving on it ever since. The Clarksfield CPUs moved graphics directly into the CPU package, and Sandy Bridge CPUs moved graphics directly onto the CPU die itself. With Ivy Bridge, Intel says it outdid itself by doubling the graphics performance of Sandy Bridge.

If you’re ready to write off Ivy Bridge as an incremental chip that you, the enthusiast, doesn’t give a damn about, you’re wrong. There’s a lot more to Ivy Bridge that makes it the default CPU for an enthusiast who doesn’t want to jump into the bigger, pricier LGA2011 socket. Don’t believe us? Read on to find out why you want this CPU instead of Sandy Bridge.

Meet the Ivy Bridge Lineup

Click to enlarge

World’s First Chip with ‘3D’ Transistors

Despite its revolutionary tri-gate design, Ivy Bridge doesn’t do much to advance x86

We’ve long dubbed Intel the “Master of the Fab.” The company’s prowess in chip fabrication is the envy of the world. Yeah, there was that little thing with the Pentium 4, which hit the process wall like a freight train, but for the most part, Intel’s mastery of chip fabrication has always made its new CPUs a tour de force of technology that makes you wonder if the company doesn’t have a crashed flying saucer hidden at 2200 Mission College Boulevard.

With Ivy Bridge, Intel again amazes with the world’s first use of tri-gate, or 3D, transistors. Also called finFETs, for fin field-effect transistors, the 3D transistors literally rise up off of the die to dramatically reduce power consumption while increasing performance. 

In a traditional planar transistor, current flows on a flat surface like a river. A gate, which ostensibly controls that flow, lies across the top of that river with contact only along a small surface. With a finFET, or 3D tri-gate, the flow of power spans a fin that juts from the surface. Instead of just contacting the surface along one dimension, the gate encircles it and makes contact on three sides.

Intel says this gives it far greater control of power and enables it to drive the signal harder while adding only a small amount to the build cost. Despite having similar architectural underpinnings to Sandy Bridge, Ivy Bridge should provide better performance while consuming significantly less power than an equivalent SB processor. So far, that seems to be panning out. A typical performance Sandy Bridge chip, such as the 3.4GHz Core i7-2600K is rated at 95 watts. The new 3.5GHz Core i7-3770K is rated at 77 watts. And those are higher-performing processors. The promise of tri-gate should pay even more dividends at lower power thresholds. Right now, Intel is only detailing its quad-core parts. Dual-core CPUs haven’t been announced yet but we’ll be curious to see how aggressively Ivy Bridge performs in notebook.

Ivy Bridge isn’t just a process story, though. It’s about keeping the chains moving. If, after all this investment in 3D transistors, the damned CPU isn’t any faster, no one would care if it were made out of the purist shimmering samite. Fortunately, that isn’t the case, which you can see in the chart on the third page. But first, let’s break it down two ways: Even Intel says Ivy Bridge isn’t a big step forward for pure x86 performance, as it’s largely a die shrink of the Sandy Bridge core. The cache remains the same and the base clocks are similar. Where Ivy Bridge appears to have an edge in x86 performance is in its lower power envelope. As you know, Intel essentially overclocks, or “Turbo Boosts,” the chip based on how much power it’s eating and how hot it’s running. So if a chip can run cooler and consume less power than its counterpart, it can run at a higher turbo clock for longer. 

Where Intel seems to have put most of its focus this time is in the GPU side. In fact, Intel says it has achieved roughly a doubling of the graphics performance over the Sandy Bridge processors. The improvement is good enough that the company says Ivy Bridge processors are capable of playing 100 games out of the box while Sandy Bridge could only play 50. Detailed info about Ivy Bridge’s graphics capabilities is on the second page, but suffice to say, it’s obviously better. Is it enough to forego a discrete GPU?

For certain uses—such as an HTPC or all-in-one PC that won’t be used primarily as a gaming machine, yes. Of course, notebook users will also be pleased to get more graphics performance from the newer Ivy Bridge parts.

Overclocking

With Ivy Bridge, Intel maintains the “K” versions that it introduced with its Lynnfield procs and continued on with Sandy Bridge. Like Sandy Bridge, Ivy Bridge isn’t hugely tolerant of bclock, or base clock, overclocking. Intel says the most you should expect is a 7 percent bclock nudge before things go sideways. Instead, overclocking will continue to rely on upping the Turbo Boost or clock ratios. Intel has enhanced Ivy Bridge a bit by increasing the maximum core ratio overclock from 59 on Sandy Bridge to 63. Ivy Bridge also now lets you change the core ratios in real time. Graphics support a greater range for overclocking, too, and Ivy Bridge will let you run the RAM up to DDR3/2667 through overclocks (DDR3/1600 is the official speed.)

Compatibility

We’ve long railed against Intel for releasing new sockets with new CPUs (remember the short-lived Socket LGA1156 and Socket 423 and numerous LGA775 versions?), but the company has stepped up to the plate for the Sandy Bridge-to-Ivy Bridge transition. As Intel promised, most LGA1155 boards will support Ivy Bridge procs if the firmware and BIOS are updated to support the chip by the board maker. However, not all chipsets will make the Ivy Bridge cut. Intel has intentionally left out support for the business chipsets Q65, Q67, and B65 while supporting consumer H61, H67, P67, and Z68. Why leave some out? Intel believes the day of an IT shop getting down and dirty and upgrading processors in an office-drone PC are long gone, so there’s just no reason to expend the resources on unnecessary support. Besides getting the latest core technology from Intel, switching to Ivy Bridge on older 6-series boards should also give you PCIe 3.0 support on some slots. 

Ivy Bridge vs. Sandy Bridge: Beneath the Surface

The 22nm-based Ivy Bridge processor is considerably smaller than its predecessor. It has nearly 400 million more transistors yet is about 25 percent smaller. What’s more interesting, however, is how much real estate is dedicated to each task on the new Ivy Bridge vs. Sandy Bridge. These die shots (not to scale) show that the almost 2x performance bump in graphics comes at the price of die space. Intel, however, discounts any criticism regarding how much emphasis it placed on graphics over x86 functionality and says just because it looks like more space was expended on graphics doesn’t mean it’s more important. Um, OK.

Sandy Bridge

Ivy Bridge

Next up: The 7-series chipset and graphics benchmarks!