VIA Technologies today formally revealed its highly-anticipated PT880 core-logic with dual-channel memory controller designed to work with Intel Pentium 4 and Celeron processors. In addition to the chipset release, Taipei, Taiwan-based logic designer also ended its 1.5 years saga concerning a new type of memory called Quad Band Memory by excluding its implementation from the new product released today.

The PT880 is VIA’s first core-logic to enable dual-channel DDR memory controller – dubbed VIA DualStream64 – a kind of memory controller able to work with two memory modules simultaneously to provide double bandwidth. The first dual-channel DDR SDRAM memory controller for desktops was originally developed by NVIDIA Corporation for its nForce chipsets in the year 2001; later similar designs were successfully created and deployed by other chipset designers, such as SiS, Intel and ATI Technologies. Besides the advanced DualStream64 technology, VIA’s PT880 offers plethora of must-be capabilities, like 800MHz Quad Pumped Bus, Hyper-Threading and AGP 8x.

It was a big surprise to see VIA not mentioning support for the QBM DRAM – a type of memory promoted by the company for years – among other specifications of the chipset. We noticed this peculiarity when MSI announced the first ever PT880-based mainboard some in October and expressed our concerns in regards this information. Now the absence of QBM support is virtually confirmed by VIA itself.

Quad Band DRAM allows to double memory sub-system’s bandwidth using the widely-spread DDR SDRAM chips. Modules, that correspond to QBM standard make use of ordinary memory chips but add a special PLL to allow half of the chips to work at 90 degrees displaced frequency, hence, data becomes available almost two times more frequently compared to ordinary modules. Basically, such way of functioning resembles a 128-bit memory module with a pair of 64-bit channels that switch, in turns, one over another.

The peak bandwidth of such RAM system can be up to 4.2GB/s when using ordinary 266MHz memory chips (PC2100), the main advantage of this technology is its presumable cost-efficiency. Since QBM technology does not require any additional signaling, QBM memory modules can maintain compatibility with widely available memory slots, such as those used for DDR or DDR-II memory. Unfortunately, keeping in mind VIA’s current position in desktop chipset market and strong DDR-II roadmap, I doubt that this exciting technology will really become a standard for desktop computers (see this news-story for some more analysis on the matter).

VIA originally planned to implement QBM support in its PT800 core-logic in 1H 2003, but then revamped its plans to add QBM to PT880 in 2H 2004. As we see now, the company has either cancelled the QBM project, or pushed it into its next-generation products due in 2004.

VIA Technologies suggests using VT8237 I/O controller with the PT880 North Bridge to provide up to 6 PCI slots, 8 USB 2.0 ports, 2-channel ATA-33/66/100/133 controller, Serial ATA-150 ports with RAID support, 6-channel audio-solution, MC97 Modem and other important input/output means.

Performance of VIA PT880 is expected to be considerably higher compared to the speed of its predecessor – VIA PT800 – because of dual-channel memory controller. According to an X-bit labs research, in memory-intensive benchmarks VIA PT880 mainboard is able to perform approximately 10% better than the PT800. Nevertheless, the PT880 is not as fast as its rivals from Intel – i875P and i865PE chipsets.

Many of the world’s leading mainboard manufacturers have confirmed design wins for the VIA PT880 chipset, including ABIT, AOpen, Acorp, ASUS, Azza, Biostar, Chaintech, DFI, Elitegroup (ECS), EPoX, Gigabyte, Jetway, MSI and Soltek.

Pricing of the VIA PT880-based mainboards is projected to be generally lower compared to the cost of Intel’s i865PE-based platforms. Availability of PT880-powered products may vary from mainboard maker to mainboard maker; MSI planned to deliver is PT880 Neo mainboards in quantities this month.