Silicon Integrated Systems Corp., one of the world’s leading developers of chipsets, said Thursday its flagship SiS656 core-logic is certified for PCI Express compliance by PCI-SIG and is also able to guarantee problem-free support for 667MHz DDR2 SDRAM thanks to validation with memory makers.

SiS656 core-logic is the company’s first North-Bridge to support PCI Express x16 bus for graphics as well as dual-channel DDR/DDR2 memory controllers that is capable to handle 400MHz, 533MHz and 667MHz memory modules delivering up to 10.6GB/s of peak memory bandwidth, substantially higher than required nowadays. The new chipset will work with Intel’s Pentium 4 and Celeron processors in mPGA478 or LGA775 packaging with 400MHz, 533MHz or 800MHz Quad Pumped Bus.

The company also offers SiS649, which is an entry-level chipset that sports Intel Pentium 4 processors, single-channel DDR or DDR2 memory as well as PCI Express x16 lane for graphics cards.

Currently there is no official support for DDR2 667MHz memory by Intel’s or VIA’s chipsets that operate with DDR2, even though a speed-boost of existing 400MHz and 533MHz speeds is officially ratified by JEDEC and nothing stops memory manufacturers to produce DDR2 at 667MHz speed-bin. SiS said it had tested the 667MHz memory with its partners among DRAM makers, including Elpida, Micron and Samsung.

“We are extremely pleased with the performance results of all Micron DDR2 SDRAM modules (PC2-3200, PC2-4200, and PC2-5300) in SiS656 platform,” said Brett Williams, Micron's DRAM PC Segment Marketing Manager.

“DDR2-400 and 533 are in mass production now, and with finishing this DDR2-667 co-validation, we believe that the memory market will rapidly adopt DDR2-667,” said Jun-Young Jeon, VP of product planning & application engineering team of memory division in Samsung Electronics.

Silicon Integrated Systems was supposed to begin volume deliveries of its SiS656 chipset back in late October. Currently market availability timeframe for the company’s top-of-the-range product is unclear.