New SiS chipset supports faster Rambus memory

Silicon Integrated Systems (SiS) last week rolled out a long-expected chipset for Pentium 4-based PCs and workstations that supports dual-channel PC1066 RDRAM (Rambus dynamic RAM), the SiS R658. The chipset is the first from the Taiwanese company to support RDRAM.

Until last year, all Pentium 4-based computers used PC800 RDRAM. That changed when Via Technologies Inc. and Intel Corp., among others, rolled out chipsets that brought support for DDR (double data rate) SDRAM (synchronous DRAM) and SDRAM to Pentium 4-based desktops. That development brought forth a surge in shipments of Pentium 4-based PCs based on these memory types, which are generally cheaper than RDRAM and, in the case of DDR SDRAM, offers comparable performance to PC800 RDRAM in many applications.

While Pentium 4-based PCs that use SDRAM and DDR SDRAM have found widespread acceptance in the mainstream market, RDRAM continues to find adherents at the high-end of the market, where the memory type's performance advantages have the most impact.

Aimed at power users, the R658 supports both 800MHz RDRAM and the newer 1066MHz RDRAM, which offers greater data throughput than PC800 RDRAM and DDR SDRAM and takes advantage of the 533MHz front-side bus -- which connects a PC's processor with the chipset -- supported by the latest versions of the Pentium 4 processor. Earlier versions of the Pentium 4 use a 400MHz front-side bus.

The R658's support for dual-channel PC1066 RDRAM, which has a maximum memory bandwidth of 4.2G bytes per second, allows a 50 percent to 100 percent increase in memory bandwidth compared to DDR, SiS said in a statement.

SiS expects the resulting improvement in overall system performance offered by PC1066 RDRAM to become more pronounced as Intel cranks the clock speed of the Pentium 4 to 3GHz and beyond. That will happen later this year, when Intel is expected to begin shipping the 3GHz version of the Pentium 4. Currently, the fastest Pentium 4 chip has a clock speed of 2.53GHz.

The R658 can support up to 4G bytes of PC1066 or PC800 RDRAM and also offers support for AGP 8X graphics. Details on pricing and availability were not immediately available.

Comparison of DRAM types used in Pentium 4-based PCs:

Memory Type SDRAM (PC133) DDR (PC2100) DDR (PC2700) RDRAM (PC800) dual channel RDRAM (PC1066) dual channel.

Clock Speed 133MHz 133MHz 166MHz 400MHz 533MHzMax.

Bandwidth 1.1G bytes/sec 2.1G bytes/sec 2.7G bytes/sec 3.2G bytes/sec 4.2G bytes/sec.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Sumner Lemon

PC World
Show Comments



Victorinox Werks Professional Executive 17 Laptop Case

Learn more >



Back To Business Guide

Click for more ›

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?