Intel bumps up the frontside bus speed for the Pentium 4 and updated 925XE core logic, but support for the faster frontside bus speeds is only for the rarified Extreme Edition processor.AMD has been steadily marching up the processor performance curve, while Intel has been scrambling for a new strategy, having to face up to the fact that scaling to 4GHz and beyond simply may not be possible with this chip architecture. Scaling up the frequency was critical to Intel's plans, as the deeper pipeline in the latest Pentium 4 architecture, based on the Prescott core, mandated higher clock speeds in order to ratchet up performance.
Even this release of the long-anticipated support for 1066MHz frontside bus is marred by Intel's lack of execution. We had anticipated two processor releases to coincide with the release of the updated version of the 925X chip set, dubbed the 925XE—one based on the 90nm Prescott core and the other a new Pentium 4 Extreme Edition. However, the higher clock rate 90nm Pentium 4 is a no-show. We do get the 3.46GHz Pentium 4 Extreme Edition. The move to a 1066MHz effective FSB (266MHz actual clock) is welcome. The P4 now is in sync with dual-channel DDR2/533 speeds.
Even so, it's not all perfect. For example, the new 925XE no longer supports ECC memory, so if you need that level of error correction, you'll have to stick with the 925X. All the other features of the 925X are present, including four SATA ports, Intel HD Audio, and the 1GB per second DMI (Direct Media Interface), a bidirectional interface between ICH6R and the MCH (Memory Controller Hub). While the 82925XE MCH no longer supports ECC, Intel engineers tweaked it a bit, and it's capable of handling lower latency DDR2 memory.
We took an Intel D925XECV2 reference motherboard and the 3.46GHz Pentium 4 Extreme Edition and put it through its paces. We also wanted to see the impact of lower latency DDR2, so we dropped in a pair of Corsair Twin2X 5300C4Pro modules and ran them at CAS 3-3-3-12. We had been unable to run the 925X version of this board even when using high speed premium modules.
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