Intel speeds Pentium 4 memory access

Three new chips use a faster memory bus, which Intel says could mean a marked boost for overall system performance

Intel is to announce on Monday a faster Pentium 4 processor with a faster bus speed, as it pushes its flagship PC chip toward a 3GHz launch by the end of the year.

Three new Pentium 4s are on the menu, said Intel, running at 2.53GHz, 2.4GHz and 2.26GHz. All three chips use a faster 533MHz front-side bus (FSB), a pipeline connecting the chip to RAM (random access memory), which Intel said can boost performance by 3 to 5 percent on some benchmarks.

The new chips are compatible with older motherboards, but to use the faster bus speed they require Intel's 533MHz FSB-enabled chipset, also announced on Monday, called the 850E. Like its predecessor, the 850, it uses only Rambus' proprietary RDRAM memory.

RDRAM delivers better performance than the competing double data rate (DDR) DRAM format favoured by semiconductor manufacturers, but the industry has shunned RDRAM because it entails royalty payments.

Intel uses the memory for high-end systems that require fast memory access, but the standard has a tiny share of the market. Intel will introduce chipsets enabling the use of other memory standards, such as DDR, later this quarter.

The 2.4GHz part costs $562, the same price as the 400MHz FSB-enabled Pentium 4. The new 2.53GHz chip costs $637 and the 2.26GHz chip costs $423, all in units of 1,000.

Intel said it is offering lower-speed chips to give buyers a broader choice. "It's a new platform and a new motherboard and chipset architecture, so we want to have a different set of speeds available to them," a representative said.

The new bus is the latest in a series of technical improvements to the Pentium 4. In January the chip got a new core called Northwood, manufactured on a more advanced 0.13-micron process. Intel has also increased the size of the on-chip, high-speed memory cache from 128k to 512k.

AMD's Athlon processor, Pentium 4's main competitor, uses a different type of architecture that achieves comparable benchmark test results to Pentium 4s with a higher clock speed. However, Athlon has 384k of on-chip cache and a 266MHz front-side bus.

Intel has announced that it plans to hit 3GHz with the Pentium 4 by the end of the year.

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