Intel 955X Express

A New Platform Already?

Only six months have passed since Intel released its last flagship chipset, the 925XE (will we ever see another chipset with the longevity of Intel’s 440BX?).We’d be elated if the Pentium D dropped right into one of those 925-based motherboards--they’re both LGA775, after all--but the processor indeed requires an entirely new platform with special concessions for dual-core processors.

The 955X MCH is covered with a rectangular passive heatsink

Notice the two PCI Express graphics slots--one is electrically x4

Fortunately, the 955X Express chipset includes more than just support for dual-core processors. The MCH now boasts official DDR2-667 memory compliance, capacities up to 8GB, and ECC error correction. Our D955XBK motherboard features four, 64-bit slots, suggesting a need for 2GB modules in order to top the board’s ceiling. Flex Memory Technology makes it possible to install memory modules of different sizes, preserving dual-channel mode even when you’re using mismatched sizes.

Intel’s documentation claims 955X only supports 800 and 1066 MHz front side bus speeds. The D955XBK’s BIOS also lists 533MHz, though, so perhaps LGA775 Celeron processors would work as well.

Time for a new power supply. This one is an EPS design

DDR2-667, running CAS 5 timings

THe D955XBK's back panel

Another interesting feature is a second x16 PCI Express graphics port on the reference motherboard. Although the 955X MCH only offers 16 lanes of connectivity, Intel’s new ICH7 I/O hub enables six x1 lanes, four of which are aggregated together to make up that slot mechanically plumbed for a video card. We tried installing a pair of GeForce 6600 GT cards and linking them with an SLI connector to no avail. Even without the connector, Intel’s D955XBK refused to recognize the second card.

The only other notable hardware addition is support for Serial ATA 3 Gbps across the ICH7’s four ports. Of course, NCQ, introduced with the ICH6, is still a standard feature. Intel’s Matrix Storage Technology now allows RAID 0, 1, 5, and 10, establishing a cost-effective alternative to expensive SATA RAID add-in cards.

More overclocking options (including unlocked multipliers)

30-percent burn-in--are you kidding?

The list of drives and boot options

Power, power, power

One Prescott core, dissipating in excess of 110W of power, is already a challenge to keep cool. Adding a second core takes even more effort. At 3.2 GHz, the Pentium Extreme Edition 840 has a thermal design power of 130W. No longer is the standard ATX power connector and 12V auxiliary input sufficient, it seems. According to Intel’s setup documentation, you either need a 20-pin ATX output, the 12V connector and another four-pin power connector or a 24-pin ATX plug and the four-pin Molex plug. Our sample system came with the 24-pin ATX connector and an eight-pin EPS output, the kind you’d normally find on a dual-processor server or workstation.

Let's go dual-core!

Tweak those timings lower, if you can

Peripheral config

That's right, Intel is giving you voltage settings