Asus drives dual Xeons with P4 chipset

Canterwood enabled for SMP?

Intel's i875P chipset, aka Canterwood, supports dual-processor Xeon chips and not just single Pentium 4s, as the part's documentation suggests.

So mobo maker Asus suggests. Its PC-DL Deluxe motherboard, detailed here, is based on the i875P, the company says, and yet has been designed to accommodate two 3.06GHz Xeon DP chips with full symmetric multi-processing (SMP) and operating on a 533MHz effective bit rate bus.

Asus' PC-DL Deluxe mobo

In all other respects, the board's specs. suggest a typical i875P-based system. It offers AGP 8x Pro; HyperThreading and PAT support; eight USB 2.0 ports and a single 1394 port; dual-channel ATA/133 and Serial ATA support.

Much of the above is delivered by the i801ER South Bridge chip, aka the ICH5R. This part provides Serial ATA and RAID support, but Asus has chosen to use a secondary RAID controller from Promise, presumably to integrate the SATA and ATA buses.

Intel does target the i875P at the workstation market, but it offers the part for single-processor P4-based systems. If it's a dual Xeon-based machine you're after, says Intel, you need the E7505 chipset.

Has Asus simply mis-labelled the chipset on the PC-DL Deluxe web page? Well, the E7505 uses the ICH4 South Bridge, not the ICH5R, and only supports 266MHz DDR - the Asus board uses 333MHz DDR. That suggests the Asus labelling is correct, and it has tapped an undocumented feature of the i875P.

Intel's reaction will be interesting, given the way Asus previously provoked the giant's wrath by revealing how it could offer PAT-like functionality with the i865 chipset family - a set of products stated by Intel as not supporting Performance Acceleration Technology. ®

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