Soon, Intel won't be the only company with a Rambus chipset for Pentium 4 PCs. Sources said Tuesday that Taiwan's Silicon Integrated Systems (SiS) will come out with a chipset that allows PC makers to connect Pentium 4 processors with Rambus-based memory. The advent of a second manufacturer could give a boost to controversial chip designer Rambus by increasing the availability of such chipsets and thus helping lower the price of building computers with Rambus memory. Until September, expensive Rambus-based memory was the only RAM that could be used with Pentium 4s. A lower-cost memory alternative has since given Rambus a run for its money. An SIS representative wrote in an email Tuesday that SIS has a plan to "support Rambus" but declined to comment further or discuss specific product plans. SIS already plans to come out with a chipset that connects Pentium 4s to less expensive, non-Rambus memory. If the processor is the master inside a computer, the chipset is the butler, endlessly shuttling data and commands between the processor and memory. Although Rambus-based memory, or RDRAM, provides a performance boost, it is also more expensive than regular memory. A 128MB module of RDRAM sells for $37 (£25). By contrast, a 128MB module of SDRAM, the most common form of memory used in PCs today, costs $4. And a 128MB module of DDR DRAM, a high-speed version of SDRAM, sells for $12 to $24. Because of the cost associated with RDRAM and other factors, PC makers have flocked to Intel's 845 chipset and cheaper forms of memory since the chipset was introduced in September. The Intel chipset, which allows PC makers to connect Pentium 4s to standard memory, is on track to become one of Intel's most popular chipsets ever, according to analysts. Gateway, for instance, said that the 845 allowed the company to cut about $100 off the price of its Pentium 4 PCs. The SIS Rambus chipset deal was hinted at in August, but at the time, the identity of the manufacturer was unknown. See Chips Central for the latest headlines on processors and semiconductors. See the Hardware News Section for full coverage. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Chips Central forum Let the editors know what you think in the Mailroom. And read other letters.