Intel Core i7 CPU tested

By Rich Brown on 12 November 2008, 5:47pm

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Intel's powerful new Core i7 desktop processor family, formerly known as Nehalem, is out very soon. We've tested the flagship, £800 Core i7-965 Extreme Edition CPU, which is representing for the Core i7 family. At launch later this month the family will include three other processors, starting at around £230.

These new chips all require a new chipset, which will only exist at first by way of a very expensive new motherboard. We don't expect mainstream users will adopt Core i7 in any variation at first, at least until the motherboard prices come down. But the well-heeled performance hounds who do make the leap will enjoy the fastest consumer CPUs on the market.

Core i7 has enough architecture changes to require a brand-new connection design between the chip and the motherboard. This is no small change, because Intel has stuck with the LGA775 (land grid array) chip socket since the days of Pentium 4. The new socket design, LGA1366, will not accept any older Intel CPUs, nor will Core i7 work on any older motherboards.

Unlike a new socket design, new chipsets aren't uncommon with updated Intel CPUs. The last three Extreme Edition chips Intel has launched all required their own new motherboard circuitry, and Core i7 is no different. Intel's new Core i7-supporting X58 chipset will only appear in very high-end boards. We conducted this review with the Intel Extreme Motherboard DX58SO board, and a new X58 board from Asus will be available too. Expect Gigabyte, MSI and Intel's other typical board partners to introduce their own new X58 boards, and we expect prices will stay at or around the £200 mark. For this reason, Core i7 will remain an enthusiast CPU until Intel introduces a more moderate, mass consumption-friendly, Core i7-compatible chipset.

Faster memory access

The reason for this platform shift has to do in part with a fundamental design change in Intel's CPU architecture. As has long been rumoured, Intel has finally adopted an integrated memory controller into its Core i7 CPUs. What this means is that instead of the CPU communicating with a separate controller on the motherboard before it can talk to the system memory, Core i7 can save a step, and essentially receive data from the system RAM directly.

AMD adopted this integrated-controller strategy in the early days of its Athlon dual-core processors, and it was one of the factors that led them to dominate the competing Intel Pentium D CPUs of that generation. Through superior design since then, Intel has regained its performance lead over AMD, and we suspect that by adding the on-chip memory controller to Core i7, Intel has only made it more difficult for AMD to find a design advantage moving forwards.

A potential complication here is that the new memory controller has three channels to the RAM. That means that unlike most desktop setups, which involve two or four memory sticks, Core i7 systems will want memory sticks in multiples of three. Hence why Intel shipped our test system with only 3GB of RAM (we got creative with a 2x 1GB, 1x 2GB RAM configuration, for 4GB total for testing), and why in high-end PCs that use the new X58 platform, 3GB, 6GB and 12GB configurations will be common. X58 will also only support DDR3 RAM, whose prices have thankfully come down over the past year. Click 'Continue' for more details, pics and benchmarks.