"There's kind of a gap. That's why we are coming out with 400-MHz DDR-I," said Tom Quinn, vice president of marketing for Samsung Semiconductor Inc., which has DDR II parts available today.

Samsung believes the fast DDR-I parts will fill a hole between 333-MHz DDR-I that is moving into mainstream desktop PCs today and the expected shift to DDR-II.

Quinn said he expects DDR II will come to PC main memory in 2004 with 256- and 512-Mbit parts running at 400 and 533 MHz. Those chips will probably appear in 1-Gbyte modules, he said.

Meanwhile, Nvidia is expected to garner attention at Comdex when it shows the NV30 using the faster DDR-II memory type for graphics frame buffers. The debut could help the company polish its image following a prolonged delay of the graphics part. The delay gave an edge to Nvidia's competitor ATI Technologies Inc., which launched its competing Radeon 9700 graphics chip earlier this year.

Although the ATI part has been demonstrated running with DDR-II memory, sources said the DRAM was running in a DDR-I compatibility mode. The part was not designed for use with DDR-II, according to sources.

As for PC main memory, it's not clear whether Intel or Taiwanese chip set makers will put much support behind the 400-MHz DDR I. "We haven't decided at this point whether to support it or not," said an Intel spokesperson.

Sources said Intel might support dual-channel 400-MHz DDR-I in its Springdale chip set due in the second quarter of 2003. The Springdale chip set is also expected to be Intel's first to support the new Serial ATA disk drive interface.

The Intel spokesperson said the company will support dual-channel 333-MHz DDR-I memories in an upcoming Granite Bay chip set for workstations by the end of the year.

Signal timing for the 400-MHz DDR-I spec is tight, which could cause PC makers difficulty supporting a broad range of memory modules that could emerge. Thus, both Intel and Taiwan chip set makers might provide 400-MHz DDR I support in their chip sets next year without marketing them aggressively.

Separately, Quinn said Samsung is developing a new DRAM technology aimed at graphics processors. Code-named GF1000, the DRAM is capable of data transfers at 2 to 4 Gbits/second and running at 1.8 volts. It is not expected to be commercially available until late 2003.