Intel Sandy Bridge review

Sandy Bridge is Intel’s latest microarchitecture, and although CPUs built to this new design still use the familiar Core i3, i5 and i7 brand names, they bring some major advances over the previous generation.

The GPU has been beefed up and moved onto the same silicon die as the rest of the CPU, making the design faster and more power efficient. New “advanced vector extensions” (AVX) help accelerate certain types of repetitive operations, promising a significant boost to applications such as media converters.

And the Turbo Boost system has been upgraded: more cores can be overclocked at once, and to higher frequencies than before, while a new “kick-down” algorithm automatically provides a brief additional boost whenever the CPU load goes up suddenly — such as when you open a program or maximise a window.

The only frustration is Sandy Bridge brings a new LGA 1155 socket. It looks identical to LGA 1156, but isn’t compatible, so upgrading will mean buying a whole new motherboard.

The chips

The new range comprises 29 new chips, of which 21 are low-power chips designed for notebooks or all-in-one PCs. We’ll have to wait until manufacturers start building them into systems to see how these perform.

But we can get an idea of Sandy Bridge’s power from the eight regular desktop chips that Intel has also launched. You’ll find full details, along with predicted launch pricing, in the table below:

Core i5 performance

To test Sandy Bridge’s performance we put Intel’s new flagship i5 and i7 processors through their paces, starting with the Core i5-2500K. It comes with a clock frequency of 3.3GHz, rising to 3.7GHz with Turbo Boost, and as it’s an unlocked K model you’re free to pump those clocks higher in the BIOS.

Testing was carried out using our real world benchmarks, on a system based on an Intel DP67BG motherboard (based on the new P67 chipset) with 4GB of Kingston HyperX 1,333MHz DDR3 RAM, running Windows 7 Home Premium from a 1TB Seagate Barracuda 7200.12 hard disk.

The i5 gave extremely impressive results compared to previous high-performing CPUs, as the graph below shows. At default speeds it achieved an overall benchmark score of 2.58 – the sort of score we normally see only from heavily overclocked enthusiast machines. Its particular strength was the multitasking component of our tests, in which it achieved a stunning score of 3.34.

Graphical performance was strong too: the P67 chipset (required for overclocking) doesn’t support Sandy Bridge’s integrated GPUs, but when we switched to a board based on the H67 chipset we found that Crysis ran at a perfectly playable 38fps at 1,366 x 768 resolution with Low quality settings. Switching up to Medium quality caused the frame rate to plummet to 13fps, but that still indicates a lot of graphical juice.

It’s worth noting that the Core i5-2500K uses the new HD Graphics 3000 integrated GPU; some other chips use the 2000 model, which has only half the shader power. But for casual games such as The Sims or World of Warcraft it looks like you’ll be able to get away without a discrete card.

There was even better news when we returned to the P67 board and adjusted the clock speeds. With just a standard Intel cooler, the i5-2500K remained stable as we turned Turbo Mode way up to 4.4GHz across all four cores. With these settings, the system achieved a gobsmacking overall benchmark score of 3.11. Those with more extravagant coolers and power supplies should be able to achieve even higher performance.