Sandy Bridge Washes Ashore

Cody Cardarelli

All other processors cease to matter in the wake of Intel’s new high-performance CPU

When your only competition is yourself, what do you do when you have to introduce your latest and greatest CPU? Commit fratricide against your own chips? If you have the muscle and war chest of Intel, then yes.

At least, that’s what Intel’s new Sandy Bridge CPU family does to the company’s existing lineup of processors—lines them up on a cliff and pushes them off, one by one.

The stellar Core i7-870? Off you go. Core i7-975 Extreme Edition? Who needs your luxury-priced ass, anyway? Core i7-950? We’ll see you in hell!

In essence, Intel’s Sandy Bridge has rendered all previous quad-core and dual-core processors obsolete in both performance and price. Yes, the top chips in Intel’s Sandy Bridge family are that fast. And they’re pretty damn cheap, too. The fastest Sandy Bridge chip, for example, will outrun the $1,000 Core i7-975 Extreme Edition, yet it costs just three bills.

Sandy Bridge isn’t just about performance, though. It’s the first time Intel will integrate a graphics core into all of its CPUs. And perhaps in its most controversial move, Intel will also finally put a nail in the coffin of overclocking for average folks. To find out whether overclocking is really dead, how fast Sandy Bridge is, and whether graphics are now suddenly important, read on.

Sandy Bridge CPU Comparison

3.4GHz Core i7-2600K
3.3GHz Core i5-2500K
3.1GHz Core i5-2400 2.93GHz Core i3-2100
Turbo Speed
3.4GHz 2.93GHz
Cores / Threads 4/8
4/4 2/4
RAM Support DDR3/1333
DDR3/1333 DDR3/1333
Graphics Clock 3,000MHz 3,000MHz
2,000MHz 2,000MHz
L3 Cache 8MB
LGA1155 LGA1155 LGA1155 LGA1155
95 watts
95 watts 95 watts 65 watts
32nm 32nm
Die Size 216mm2 216mm2
216mm2 131mm2
Transistor Count
995 995 995 504
Bulk Price
$184 $117

Talking the Tock

If you’re not up on current events, Intel has followed a “tick-tock” cadence in its chip making these last few years. A “tock” represents the huge, sweeping changes to processor microarchitecture that we all get hot under the collar for. That’s eventually followed up with a tick, or more minor improvements to the existing microarchitecture.

One well-known tock was the original Core 2 “Conroe,” which literally saved Intel’s bacon and finally put that bad nightmare of a microarchitecture known as Netburst in its grave. Another tock was the Core i7 “Nehalem.” It was a revolutionary step for Intel wherein the memory controller got integrated into the die and the ancient front-side bus was jettisoned.

So, what’s so special about Sandy Bridge that it earns the distinction of being a tock? It’s hard for us to single out just one quality, but certainly a key feature is the fully integrated graphics core. With Sandy Bridge, Intel has completed its commingling of graphics and compute processing by moving an improved graphics core directly into the 32nm die. Intel had previously integrated a separate 45nm graphics core inside the CPU of its Clarkdale (and mobile Arrandale) chips, but it was a bit of a hack. Since the GPU is now integrated in the die, all second-generation Core i3/5/7 CPUs will include graphics—so no more of that some-chips-get-graphics-and-some-don’t hullabaloo that happened with LGA1156-based CPUs.

Sandy Bridge represents a far more elegant integration of graphics, and some would argue that Intel has beaten AMD to the Fusion punch by pushing its parts out first. Intel even designed a new ring bus that services the graphics processor and the x86 cores and L3 cache. Besides offering boatloads more bandwidth than the previous iteration, the ring bus allows the L3 cache to run at the clock speed of the CPU. Previously, the L3 cache was included in the “uncore” part of Nehalem that was clocked down. These higher clocks, obviously, increase bandwidth and reduce latency.

The x86 cores themselves are evolutionary developments of the Westmere design, so all chips now get encryption/decryption acceleration care of the AES-NI instructions. One key change is the addition of Intel’s Advanced Vector Extensions, or AVX. AVX instructions are designed to vastly improve floating-point performance across the board for the increasingly media-rich world we live in. AMD also has plans to support AVX in its upcoming Bulldozer chip, so AVX instructions are a shoe-in for support. However, as always, specialized instructions take time to flourish. At press time, we couldn’t find any AVX-enabled applications, and full OS support for AVX won’t happen until Microsoft releases Service Pack 1 for Windows 7.

Graphics: Good but Not Great

You know you’re in bizarro-world when one of the most touted features of Sandy Bridge isn’t an x86 innovation, but the integration of a graphics core. While Intel once pooh-poohed GPU-accelerated encoding as pure suckage, it’s a check-off feature on Sandy Bridge that the company is quite proud of. Some folks might snicker at this, but we doubt that Nvidia and AMD are very amused, as Intel has a history of enacting 180-degree spins with a technological vengeance. Think of the original Core 2 or the Core i7. Both represented healthy portions of crow-eating by Intel, but both chips were also untouched by rivals for years.

While the graphics in Sandy Bridge are certainly improved, don’t expect miracles. If you want Warcraft or Starcraft at standard resolutions without shelling out $75 for a discrete GPU, then Sandy Bridge might work for you.

Graphics aren’t just about gaming, however. The new graphics core, when combined with a chipset that supports video output ports (the H67 and Q67 chipsets), will support Blu-ray 3D output over HDMI 1.4a, more video-processing options to enhance playback, and for laptops equipped with Wireless Display, full 1080p to a WiDi adapter hooked up to your TV. Intel’s graphics-based encoding/transcoding is called Quick Sync Video. Quick Sync Video is building support, but it has the drawback of being incompatible with a discrete graphics card. The onboard graphics core is disabled with discrete graphics, becoming, essentially, a waste of transistors. Ideally, we would like to see switchable graphics on the desktop that let you turn off the power-hungry ATI or Nvidia card when you don’t need it and instead use the power-sipping Sandy Bridge chip. This is done on notebooks, so why not on desktops?

The upshot regarding the new, improved graphics in Sandy Bridge is, temper your expectations. For an HTPC not intended for gaming, it’s a great solution. For your mom’s machine, more than enough. For you? Fuhgettaboutit.

Turbo Boost Made Better

Although there are numerous sources for the performance enhancements in Sandy Bridge, Turbo Boost 2.0 deserves special mention. Intel has been refining its automatic-overclock feature for years, and Sandy Bridge shows the confidence Intel now has in its silicon and how far it can be pushed. Older versions of Turbo Boost would “turbo up” but not if all the cores were being pushed. The best results from Turbo Boost came in lightly threaded applications that hit just one or two of the cores. Turbo Boost 2.0 will throttle up even if all four cores are under load. The boost will only drop off if the chip’s power control unit senses that it’s near overheating. Desktop parts get a healthy dose of boost—the top-end 3.4GHz Core i7-2600K will clock up to 3.8GHz—but mobile gets a bigger shot. The 2.5GHz Core i7-2920XM, for example, will boost all four cores up to 3.2GHz. A single-threaded app on the same chip could see the CPU boosted up to 3.5GHz—that’s a 1GHz overclock in a notebook!

The Death of Overclocking

That brings us to the most controversial aspect of Sandy Bridge: the death of overclocking as we know it. At least, that’s probably what most enthusiasts will say when they hear the news that it will be extremely difficult to overclock the vast majority of Intel’s new Sandy Bridge chips.

As you know, there are two ways to overclock a Core i3/5/7 chip: increasing the Turbo Boost multipliers (which can only be done on Extreme chips and K chips) or upping the base clock, or bclock. With LGA1156 and LGA1366 CPUs, the bclock relied on the clock signal being generated by a separate clock on the motherboard. With LGA1155, Intel has integrated a clock-signaling device into the chipset itself, and now when you goose the bclock, everything runs out of spec and gets ugly fast. With Sandy Bridge, you shouldn’t expect a bclock overclock to net you more than 5 percent at best. That’s a damned shame to those of us used to taking any old Core i3/5/7 and pushing the bclock from 133MHz up past 200MHz.

Conspiracy theories are already swirling that Intel did this because too many people were overclocking cheap chips instead of buying pricier ones. The company denies this. It says the main reason it moved the clock into the chipset was to save costs. While it may seem insignificant, integrating the clock into the chipset saves a board maker $5, which is a big deal. Intel officials say they didn’t intend to put a clock block on our bclock, but it was an unfortunate casualty of engineering. Officials say it’s quite possible that future iterations could see the return of bclock overclocking.

As a peace offering, Intel says that Sandy Bridge offers a couple of concessions to overclockers. The chip lineup includes two “K” CPUs: The 3.3GHz Core i5-2500K and the 3.4GHz Core i5-2600K. Both feature unlocked Turbo Boost multipliers and unlocked memory multipliers. Even better, the price premium for the K parts over non-K equivalents is minimal. The Core i7-2600 runs $294, while the Core i7-2600K will set you back $317. The price difference between the 2500K and the 2500 is just $11. Even for enthusiasts who aren’t into overclocking, the K parts are a no-brainer. We ran ours near the 5GHz range on air with no issues. That’s unheard of with previous quad-cores without the aid of exotic cooling.

For non-K parts, Intel is also throwing you a bone by letting you overclock up to four bins which isn't too shabby for non-enthusiasts.

So, do we buy Intel’s explanation? Yes and no. Saving board makers $5 we get. But there are other aspects that make us think it ain’t just about $5. Non-K chips also feature locked memory multipliers, so the fastest they’ll run is DDR3/1333 on H series chipsets. That’s certainly not related to money. Why couldn’t Intel have unlocked all of the chips as it did with the K parts? The ultimate judge of how much backlash there will be is consumer response.

Will enthusiasts make a beeline for AMD? Our bet is no. Sandy Bridge’s performance and the fact that each chip overclocks itself so damn well means that people will probably be OK with it.

The upshot, folks, is that Sandy Bridge offers a truly amazing amount of performance at previously unheard-of prices.

The Sandy Bridge Architecture up Close

Sandy Bridge is a vast improvement over the previous Clarkdale/Arrandale-based Core i3 and Core i5 chips. Previous Core i3 and i5 CPUs used a multichip package joined by a fast QPI connection inside the heat spreader. Every Sandy Bridge chip uses the same monolithic die that includes an elegant layout of a “processor graphics” core alongside two or four cores and a fat load of L3 cache. To join all of these together, Intel has designed a new ring bus that offers a phenomenal amount of bandwidth to all of the parts.

The bandwidth varies based on the number of cores on the ring bus and the clock speed. That’s because the L3 cache now runs at full core-clock speed. Previously, the L3 cache ran at the lower “uncore” speed. In a typical quad-core Sandy Bridge chip running at 3GHz, roughly 384GB/s of bandwidth is available from the L3 cache. As with Lynnfield and Clarkdale, an integrated memory controller and a single x16 PCI-E 2.0 is embedded in the core as well. The connection to the peripheral control hub, which we call the south bridge, comes via a single 20Gb/s Direct Media Interface connection.

One Socket to Rule Them All?

We’ve been warning readers that LGA1156 was a dead man walking for months now. Well, meet its replacement: LGA1155. Yup, just one pin and your board is officially obsolete. With LGA1155, Intel is introducing four new chipsets, with only two that matter to you: H67 and P67. There’s no native USB 3.0, but SATA 6Gb/s is now supported on up to two ports of the south bridge—support on all the ports would be too costly. The key differences between the two chipsets is that H67 offers support for the internal graphics, and overclocking will only work on P67.

Above is the old LGA1156 and below is the new LGA1155.

One big question is whether LGA1155 will exist only for Sandy Bridge. There have been rumors of moving the new Xeon socket LGA2011, with its quad-channel memory, to consumers later this year, but we understand that Intel is now considering going back to a single-socket lineup. LGA1366 will be supported with updates this year, but after that, LGA1155 could be the only game in town.

Out with the Old CPU, In with the New

Physically, the new Sandy Bridge LGA1155 processors look almost the same as the previous LGA1156 CPUs based on Clarkdale and Lynnfield. The key difference is under the heat spreader. Can you plug an LGA1155 chip into a LGA1156 board? Nope. Every time Intel does this, we wonder if the company is just trying to piss us off. And as always, Intel says no. It had to make the socket changes to meet the design needs of the new Sandy Bridge CPU. That won’t help people who just bought a brand-new LGA1156 board and CPU and feel burned yet again by another socket switch from Intel. There’s good news, though: The new socket doesn’t require a new heatsink. The mounting holes are compatible with existing LGA1156 coolers.

On the left is the new LGA1156 and on the right is the old LGA1155.

Sandy Bridge Meets the Benchmarks

No matter how you slice it, Intel’s new 2600K is a cold-blooded killer

People will look for a lot of reasons to hate Sandy Bridge: Overclocking is limited to the K parts, you have to buy a new board, and the graphics core is switched off once you install a GPU. But once you get to raw, ripping performance, it’s hard not to gush over Sandy Bridge. Frankly, it’s an astounding amount of performance for
the money.

The top-end Core i7-2600K smashes every other quad-core Intel chip by healthy margins. This is aided by the new microarchitecture, the ring bus, and other magical stuff, we suppose, but we see no reason to buy any other CPU for the money. Even the once-powerful Core i7-975 Extreme Edition is flatly punched in the nose by the 2600K. While the 975 is long gone, you can extrapolate that the 2600K will outgun the Core i7-950, i7-930, and the poorly priced i7-960. Against non-Intel chips, it’s no contest. AMD’s hexa-core Phenom II X6 1090T, which was already getting beaten up by existing Hyper-Threaded Core i7 chips, also takes a serious thrashing from the Core i7-2600K.

Even the mighty Core i7-980X loses a few benchmarks to the Core i7-2600K chip. These are mostly in benchmarks that can’t exploit the six-cores of the 980X, and where the Turbo Boost 2.0 gives the Sandy Bridge part a key advantage.

Certainly, overclocking the older Intel parts and the Phenom II can help, but the 2600K, we must add, also overclocks like a champ. So, haterz, set aside your hate. If performance is what you care about (and you don’t want to shell out for a $1,000 hexa-core), Sandy Bridge, particularly the K versions, should be on your radar.


3.4GHz Core i7-2600K
2.66GHz Core i5-750
2.8GHz Core i7-860
2.93GHz Core i7-870
3.33GHz Core i7-975 Extreme Edition 3.33GHz Core i7-980X 3.2GHz Phenom II X6 1090T
Premiere Pro CS3 (sec)
581 539 504 453 749
Sony Vegas Pro 9.0c (sec) 3,007
3,863 3,531 3,244 2,675 5,010
HandBrake DVD to iPhone (sec) 1,298
1,360 1,247 1,170 941 1,580
MainConcept 1.6 (sec) 2,134 3,092
2,735 2,486 2,308 1,827 2,816
Cinebench 10 64-bit 23,259
14,455 17,516 19,197 20,147 27,479 17,892
Cinebench 11.5 64-bit 6.87 3.83 5.15 5.54 5.99 8.92 5.67
POV Ray 3.7
2,810 3,883 4,497 4,236 6,557 4,656.5
Photoshop CS3 (sec)
123 100 91 89 130
Adobe Lightroom 2.6 (sec) 394 603
469 422 418 419 426
ProShow Producer 4 (sec)
1,007 1,425 1,382 1,290 1,208 1,092 1,669
Bibble 5.02 (sec)
142 122 120 97.2 145
PCMark Vantage 64-bit Overall
8,903 9,120 9,260 10,470 7,481
Fritz Chess Benchmark (KiloNodes/s)
8,407 10,997 11,995 12,738 12,733 11,219
Valve Map Compilation (sec) 76 110 116 106 100 99 132
Everest Ultimate MEM Copy (MB/s) 16,994
15,445 15,372
17,712 13,086 11,043
Everest Ultimate MEM Latency (ns) 36 54.3
59.8 61.3 51.6
SiSoft Sandra RAM Bandwidth (GB/s) 16 17
23 20 13
3DMark Vantage CPU 53,599 44,594
51,321 62,893 44,587
Valve Particle test (fps) 180 111
174 259 120
Resident Evil 5 / low-res (fps) 132 110.3
130.7 134.1 100.3
World in Conflict / low-res (fps) 306 256
317 358 162
Dirt 2 / low-res (fps) 162 155
157 155.7 121
Far Cry 2 / low-res (fps) 165 146.53
158.2 158.6 99
Price $317 $196 $284
$999 $999 $235

We used 64-bit Windows 7 Professional, 4GB of RAM DDR3/1333 (for the dual-core chips) or 6GB of DDR3/1333 (for the tri-channel chips), a Western Digital Raptor 150 10,000rpm hard drive, a GeForce GTX 285, and the same graphics driver for all of our test configurations.

Correction: The original article contained an error which stated that the non K-series CPUs limited overclocking to a single core. The non K-series Sandy Bridge CPUs actually allow you to overclock four cores up to four bins. The article also failed to say that memory overclocking limits are only on H-series chipsets. Maximum PC regrets the error.

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