Intel 840 Chipset
The i840 was designed for workstations and small to midsize servers. The most significant difference to i820 are the two Rambus-channels that i840 is hosting. Both channels need to be equipped with the same amount of RDRAM and so i840 can take advantage of 'interleaving'. This interleaving of the two channels can almost halve RDRAM's latency and at the same time the two channels can together supply double the amount of data. Therefore i840 is less sensitive to software that jumps all around memory (e.g. database software) due to the reduced latency and it can deal with much larger memory streams. With PC800 RDRAM i840 offers a data bandwidth of up to 3.2 GB/s, with PC600 RDRAM it's 2.1 GB/s, which still beats i820 with PC800 RDRAM. i840 does not support the PC700-spec. It's either fish or flesh, either PC800 or PC600.
Intel's 840 is from the same generation as i820. Thus it also supports SDRAM as long as at least two MTH-chips are used. It also supports AGP4x, ATA66 and it uses the Intel hub architecture.