Intel Core i7-860 review

The Core i7-860 is one of Intel’s first three CPUs based on the Lynnfield core (the other two being the Core i5-750 and the Core i7-870). It’s a refinement of the Nehalem microarchitecture first revealed in the Core i7-900 series CPUs.

Like its stablemates, the i7-860 combines four CPU cores on one 45nm die, with on-chip memory and PCI bus controllers. The 8MB of shared L3 cache remains too. And rather than the LGA 1366 format of the older Core i7s, Lynnfield chips use the more petite new LGA 1156 socket.

The most exciting development is Turbo Mode, which borrows power from idle CPU cores to overclock active threads. This was introduced with the first Core i7 CPUs, but those parts could boost a single thread only by a maximum of 266MHz, whereas Lynnfield can raise the speed of a single core by as much as 667MHz – a significant enhancement.

Going by model number, the i7-860 is the most junior Core i7 CPU yet released. But it retains Intel’s Hyper-Threading technology, allowing it to appear to the OS as an eight-core CPU. And its 2.8GHz clock speed (disregarding Turbo Mode) is actually higher than that of the 2.66GHz Core i7-920.

Performance

So it’s no great shock that the Core i7-860 is a strong performer. When tested in a Gigabyte P55 motherboard with 2GB of DDR3-1066 RAM, an ATI Radeon HD 4550 graphics card and a Seagate Barracuda 7200.12 hard disk, it achieved 1.95 in our real world benchmarks – not far off the older Core i7-940, which scored 1.98 in a similar configuration.

And though thermal design power for the Core i7-860 is quoted as 95W, our test system idled at a stunningly low 60W. Even when we drove all four cores up to full load, total power draw peaked at just 124W. Some older Core i7 systems draw that much when idle.

Price

The Core i7-860 isn’t terrifically cheap, with early prices coming in at £203 exc VAT. Since the Core i5-750 provides 95% of the performance (in our real-world benchmarks) at 70% of the cost, it’s hard to recommend this model. Alternatively, AMD’s Phenom II X4 965 delivers similar performance at a lower price — albeit with a much higher power consumption.

Then again, the i7-860 is far better value than the Core i7-940, which will set you back well over £300. And P55 motherboards are significantly cheaper than X58 models. So if you’re building a workstation, or perhaps if your workload really demands HyperThreading, this pricey chip could still be your best option.

Author: Darien Graham-Smith