Intel’s 'Sandy Bridge' processors: How do they stack up?

Intel’s “Sandy Bridge” processors are nearly here, and our lab results are in.

Intel has pulled back the proverbial curtain on their second-generation Core processors, which were previously known by the codename "Sandy Bridge." The new CPUs are built on a brand new microarchitecture, and feature a number of enhancements, including improved integrated graphics performance.

For a detailed run-down of all that Sandy Bridge has to offer, be sure to check out our overview of the new features baked into the second-generation of Intel's Core processors.

Testing Sandy Bridge

For our tests, We'll be looking at a pair of processors: the 3.3GHz Core i5-2500K ( $216), and the 3.4 GHz Core i7-2600K ($317). For the Core i5-2500K, Intel provided the DH67BL "Bearup Lake" motherboard, which is equipped with Intel's second-generation integrated graphics on the H67 chipset. For the Core i7-2600K, we're using the DP67BG "Burrage" motherboard, sporting the performance oriented P67 chipset.

New CPUs, new chipsets, and -- much to the chagrin of serial upgraders -- new sockets. The second-generation Intel CPUs are using the LGA-1155 socket, so you'll need to pick up an entirely new motherboard if you're planning on picking up a new CPU.Both testbeds were outfitted identically: 4GB of DDR3 RAM, a 1 TB hard drive, an AMD Radeon HD 5870 graphics card, and an optical drive for loading applications. Occasionally, the graphics card on the i5-2500K testbed was removed for comparison testing of the H67 chipset's integrated graphics. The processors were left at their stock clock speeds, while the machines provided by MicroExpress and Origin sported generous overclocks. Lets check out the results!

Performance: Worldbench 6

First up is PCWorld's WorldBench 6 benchmark suite. For the uninitiated: WorldBench consists of a series of tests using real world applications to gauge a PC's performance. A series of applications run, simulating a typical workload. A WorldBench score is then compiled based on how long it took the machine to complete tasks. The results on our reference boards are impressive: Our Core i7-2600k earned a WorldBench score of 156, while the Core i5-2500K earned a 150.

Let's put those numbers in perspective. Back in August we reviewed Maingear's F131, a $2000 Mainstream desktop equipped with a Core i5-655K processor, 4GB of RAM, and a 1TB hard drive. It earned a WorldBench score of 152, but only after Maingear overclocked the CPU all the way up to 4.5GHz.

MicroExpress sent over theMicroFlex 25B, an $850 desktop equipped with the Core i5-2500K, 4GB of RAM, and a 300GB hard drive. It was overclocked to 4.1GHz, and earned a staggering 188 on WorldBench -- a result typically reserved for the upper echelons of the Performance category, in machines that cost upwards of $2000.The top tier isn't exactly slouching, either. Origin provided their latest Genesis, equipped with a Core i7-2600K overclocked to a blistering 5GHz. This $7000 juggernaut is packed to the gills with all of the latest and greatest hardware, and earned a 223 on WorldBench -- the highest score we've ever seen. Be sure to check back for full reviews on both machines.

Performance: Games Testing

Our test beds were well equipped to handle gaming too, delivering strong performance across the board on our games tests. We ran four modern games, to get a general idea of performance: Codemasters' Dirt 2, Activision's Call of Duty 4, Eidos' Just Cause 2, and GSC Game World's S.T.A.L.K.E.R.: Call of Pripyat. The tests were run at a 2560-by-1600 pixel resolution, with the highest possible settings.

That their performance is nearly identical isn't too surprising. The Core i5 2500K doesn't offer Intel's Hyper Threading technology, but in this case, the graphics card is the limiting factor.

For a clearer view, we'd have to look at an application designed to sprawl across as many cores as possible. Consider Maxon's Cinebench CPU benchmark. This particular test can utilize up to 64 processor threads. The 4-core, 8-thread Core i7-2600K was 25% faster than the 4-core, 4-thread Core i5-2500K.

Intel's second-generation of integrated graphics aren't quite ready for enthusiast level gaming. When the graphics card was removed, our Core i5-2500K testbed failed to offer playable frame rates at any resolution, on any of our tests.

But all is not lost: new features like support for 1080p Blu-ray playback and stereoscopic 3D will make things a bit more appealing for Compact desktops, or smaller notebooks and netbooks that rely on integrated graphics to maintain a low profile.

Media Encoding with Intel's Quick Sync

Of special interest on the revamped integrated graphics is the new, hardware-based accelerated video processing -- Intel has dubbed it Quick Sync. Quick Sync is designed to speed up video encoding tasks without the aid of a discrete graphics card, when you're using software that supports the functionality.

It's all invisible to the end user. We gave Quick Sync a try, and compared its performance to video encoding on several other machines. We tried the Core i5-2500K testbed running on Intel's integrated graphics and using an AMD Radeon 5870, the Core i7-2600K equipped with an AMD Radeon 5870, an All-in-One desktop equipped with a Core i3 processor and 4GB of RAM, and a midtower desktop sporting an AMD Phenom II X6 processor, 8GB of RAM, and a Radeon HD 5750 graphics card.

We used the latest version of Cyberlink's Media Espresso 6, which supports Intel's hardware decoding, and the open-licensed (and hilarious) Big Buck Bunny. It's a 900MB 1080p clip that's just under 10 minutes long. We encoded the clip for playback on an iPhone 4 and an iPad, at 720p. On the chart, "IGP" refers to a test using the Core i5-2500K's integrated graphics.

The results are impressive -- Intel's new integrated graphics beat out machines equipped with discrete graphics cards in all but one instance, and ran circles around the Core i3-based All-in-One. CPU utilization hovered at around 35 - 40%, and the system responded snappily even while churning through my video processing demands.

AMD and Nvidia would do well to take note, as this is a clear shot across the bow at discrete graphics cards. If your video demands are heavy and you've no interest in gaming, a PC equipped solely with Intel's second-generation integrated graphics has become a palatable option. Integrated-only Compact desktops can be had for as little as $300 -- expect to see many PC manufacturers touting quiet, small PCs as dedicated media machines with a bit more muscle this year.

Power Efficiency

To get an idea of the energy savings these new CPUs provide, we'll look at two sets of data. First, we'll compare our test beds with PCs we reviewed in the last few year, that earned similar WorldBench scores. These charts look at the power consumed while the PC is idle, as compared to the machines WorldBench score.

Similar performance results, but fairly different idle power ratings. The specifications of these machines vary (Maingear's F131 is equipped with a pair of graphics cards), but they offer a general idea of the power use we expect from machines that hit these performance numbers.

For a different take, let's pit our test beds against machines that consume about as much power when idle.

While power consumption here is similar (and at times better) than the Sandy Bridge testbeds, performance ultimately suffers.

The Next Generation

Intel has a real winner on their hands here. The second-generation Core processors manage to outpace their predecessors, while keeping power consumption low. But more importantly, their oft-maligned integrated graphics platform has received a much-needed shot in the arm.

The processors launching over the coming weeks fall right into the middle of the road, performance-wise. We can expect second-generation Core i3 processors, and higher end Core i7 processors to arrive later on this year. With CES 2011 just a few days away, there are sure to be plenty of announcements -- stay tuned for our coverage!

This story, "Intel’s 'Sandy Bridge' processors: How do they stack up?" was originally published by PCWorld.

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