SIS655 with two memory channels for the Pentium 4
At the stands of some mainboard manufacturers, the first test samples with the new chipset from SIS, the SIS655, for the Pentium 4 were shown at CeBIT. The special thing about this chipset is that two memory channels are now available.
The memory clock is 133 or 166 MHz . With a memory channel, this results in a bandwidth of 2.1 or 2.7 GByte/s. If you now distribute the memory accesses over two channels, the result is 4.2 GB/s with the PC2100 memory modules and 5.4 GB/s with the PC2700 memory chips, which of course also affects the performance.
This technology is also used in the nVidia nForce 420 and 415 chipset for the Athlon and their successors and ensures a decent performance boost. Unfortunately, the whole thing also has a disadvantage. The dear costs. Because in order to benefit from the higher memory bandwidth, at least two identical memory modules must be used. Furthermore, due to the additional pins and lines, the production of the mainboards is considerably more expensive compared to conventional mainboards with only one channel.