Nehalem, Intel's Core i7 CPU, Unveiled

Is the Nehalem (Core i7) going to be one of those new pieces of hardware that empties your wallet? If so, how's it going to sell in these tough economic times?

Intel Nehalem's pricing surprises us, in terms of affordability, at least at the low end. Three Core i7's will be introduced at launch:

• 2.66-GHz Core i7-920, priced at $284;
• 2.93-GHz Core i7-940, priced at $562;
• 3.20-GHz Core i7 Extreme 965, priced at $999.

Just FYI, this is based on the typical chip pricing of lots of 1,000. You can expect your price to be higher.

Of course, you'll need a new motherboard, and probably new memory, as the integrated memory controller only supports DDR3.

Let's take a look at the updates / changes to the new Nehalem (Core i7) CPU.

The original Core 2 line, which was launched two years ago, was built on a 65-nm manufacturing process. In late 2007, Intel began shipping newer versions of the line, Penryn 45-nm CPUs. The Core i7 continues to use the 45-nm process.

However, Intel is dropping the aging Front-Side Bus (FSB) with this CPU. Instead, we now have what Intel calls Quick Path Interconnect (QPI).

QPI is similar conceptually to AMD's HyperTransport. A 20-bit interface with bi-directional communication, Intel’s first gen QPI will support either 4.8 gigatransfer/s for the Core i7-920 / i7-940 CPUs or 6.4 gigatransfer/s for the Core i7 Extreme CPUs.

We already said the Nehalem (Core i7) will support DDR3 memory only; Intel has put a triple channel memory controller onto the CPU, joining AMD, who first added an integrated memory controller to their Athlon 64 CPUs.

Adding cache to a CPU is a favorite way to increase performance, and Core i7 has three levels of cache.

• Each of the four cores in the Core i7 gets 32K of L1 Data and 32K L1 Instruction cache; 256KB of L1 cache total.
• Each core gets 256KB L2 cache, a total of 1MB.
• There's a shared L3 cache; 8MB shared amongst all four cores.

The Core i7 CPUs will be HyperThreaded, which was first introduced in the Pentium 4 CPU's Netburst architecture. This will allow the Core i7's four cores to be recognized as eight virtual cores by the OS.

SSE4.1, was Intel’s prior addition to their multimedia instruction set, and was added to the Penryn CPUs, with 47 new instructions. SSE 4.2 is added to the Core i7; it adds seven new media acceleration instructions.

Power, power, power, and we don't mean horsepower, but power consumption is a focus of all new CPUs. The Core i7 has integrated power sensors and an integrated Power Control Unit. We're not talking a really, really green CPU, but this PCU will allow the processor to perform real-time monitoring of each core power usage.

That sort of dovetails into Turbo Mode. Way back in the day, some PCs came with a Turbo button you could push. More recently, you could adjust CPU frequency in your BIOS to overclock your PC. Intel's Turbo Mode is kind of like automatic overclocking. If there are idle cores in the CPU, power from those cores are routed to the active cores, meaning that power is not wasted, while performance is increased.

Those are the highlights. Performance-wise, let's just sum it up in one four-letter word: fast. We're not going to review the CPU here, but rest assured, the Nehalem is a game-changer.