At best, the winner of this contest will achieve only niche status, industry experts say, yet that is hardly taking the edge off a debate to determine which is the better choice.

At present, dual-channel systems seem to have the edge, with recent announcements from Intel, Via Technologies and Silicon Integrated Systems (SiS), all of which are in various stages of rolling out chip sets for high-end PCs or servers. For supporters, the architecture represents a new way to quickly match the pace at which Intel Corp. is boosting front-side bus speeds.

The dual-channel chip sets, such as Via's P4X600, SiS' 655 and Intel's E7205, will start shipping this quarter. Via says its offering will be ready to ship in volume by the end of the first quarter. Via and SiS will support 5.3-Gbyte (DDR333) bandwidth and Intel, 4.2 Gbytes (DDR266).

Meanwhile, Kentron Technologies Inc., which developed quad-band memory, is pushing QBM as a relatively hassle-free, low-cost way for PC makers to eliminate system bottlenecks. Earlier this month, Kentron gained traction when Via said it would support QBM533 in its upcoming P4X800 chip set, which will also include DDR-1 and DDR-2 memory controllers.

Via's support has set the stage for a showdown between the architectures. Having originally pushed its scheme as a potential server technology, Kentron is changing its pitch by saying QBM is suitable for the masses. Chief executive officer Bob Goodman believes that dual-channel and QBM can coexist, with dual-channel carving its groove at the high end, where system costs can absorb the premiums associated with potential additional motherboard layers and spacing issues associated with more bit lines for the second memory bus.

"But in the lower-end PCs, the higher-volume world, QBM is the perfect solution because it does use existing DDR-1 devices to balance the front-side bus of the P4 at 533 MHz today and 667 MHz very soon," he said.

QBM modules have two double-data-rate banks, running on alternating clock schedules. Each DRAM is linked to a FET, which regulates and merges the output into a 4-bit data stream for every 10-nanosecond clock cycle. In effect, QBM delivers 4 bits per I/O cycle instead of 2 bits with normal DDR and 1 bit with standard SDRAM.

Big announcements coming?

Because the changes are on the module, Kentron says, QBM makes a better solution for more price-sensitive systems. Goodman said he is also talking with other chip set vendors to offer support and expects major memory module vendors to announce products by the end of the year.

Intel favors dual-channel systems and doesn't look likely to lend chip set support to QBM — and that, by default, will restrict the technology. "One of the problems with QBM is that, yes, you get double the data bandwidth but you only have the same address command bandwidth as DDR-1," said John Halbert, Intel's principal engineer of memory technology. That will limit its performance against dual-channel systems and, later, DDR-2 systems, he said. "We also doubt the scalability of QBM."

That debate must wait a year or so until Kentron tackles DDR-2, but for now, Goodman said, QBM technology will be scalable into the next generation.

As systems hit the market, it looks as if dual-channel DDR may settle into servers and workstations and QBM may find its niche in high-performance desktops. That will also be where DDR400, the 400-MHz double-data-rate DRAM scheme, will find some allure, even though it will give up about a gigabyte of throughput to QBM533 systems.