Under the 600-Series Hood

It’s About Time…

Although Intel can hardly be expected to make a big deal of its 64-bit adoption (after all, it’s following in AMD’s footsteps here), the feature is significant to accelerating mainstream acceptance and encouraging 64-bit software development. There are already a few applications available in 64-bit trim, but the vast majority will have to wait until Microsoft officially unveils an operating system in 64-bit form rather than the existing release candidates. From a hardware perspective, relatively little is needed to support the technology. Existing motherboards require updated BIOS files and that’s about it.

Power management functionality is similarly easy to implement and use. Properly configured systems employ a number of features initiated in different ways to reduce the Pentium 4’s power consumption. The first is an enhanced halt state that reduces frequency through an adjustable bus multiplier, subsequently reducing voltage, and in turn, minimizing draw. The TM2 (thermal monitor) differs in that it responds to a processor request based on thermal load by changing frequency and voltage, cooling the core by up to 40 percent without a massive performance degradation. The goal there is to prevent the Pentium 4 from overheating should a heatsink dislodge or fan fail. Finally, EIST functions according to processor load based on operating system monitoring. Lower frequencies are applied during light work loads, while higher speeds kick in as processing demands rise. Currently, only Windows XP with Service Pack 2 supports the feature, though Windows Server 2003 will also recognize EIST once that update is finalized.

The 2MB die is much bigger

Intel's old Prescott core is significantly smaller

And then there’s the 2MB L2 cache, a much-needed add-on that aims to improve performance by deemphasizing system memory, as opposed to AMD’s strategy of incorporating an on-die memory controller to accelerate memory accesses. The extra cache raises the chip’s transistor count to 169 million, while increasing die size to 135 square millimeters. Of course, the Execute Disable bit that characterizes 500-series processors with a J suffix is also included as a security measure. As with EIST, Execute Disable requires Windows XP Service Pack 2 for proper recognition.

A New Extreme

Existing 6-series chips still run on an 800MHz front side bus, limiting available bandwidth to 6.4GBps. Meanwhile the Pentium 4 3.46GHz Extreme Edition still gets that 1066MHz setting. Doesn’t seem fair? Well, Intel is also introducing a faster Extreme Edition that centers on the Prescott core, representing the first ever architectural change for Intel’s flagship offering. Running at 3.73GHz, the Extreme Edition sets itself apart by operating a bit faster than the top-end 3.6GHz 660 model and supporting a 1066MHz bus.

There’s no extra cache this time; the EE rests solely on its frequency and bus. Thus, it’ll likely be even harder to justify spending $1,000 on the chip. Conversely, at least the new Extreme Edition supports 64-bit processing and the Execute Disable Bit. Apparently, Intel thought better of incorporating power management functionality into a take-no-prisoners processor, so you’ll have to do without EIST on the EE. Then again, if you can afford the price tag, this month’s electricity bill probably isn’t much of an issue, either.