Originally, the one Pentium 4 platform, based on Intel's 850 chipset, was supporting RDRAM memory only. Intel's reaction to the difficult foothold of RDRAM came pretty late. In July Intel released the 845, only supporting PC133 SDRAM.

One month later VIA was bold enough to release the first Pentium 4 chipset with DDR-support, but this core logic is still on shaky legal ground, keeping the big motherboard makers from offering products with the P4X266.

In Fall SiS launched its 645 chipset, which sports not only DDR-support, but also a high-speed version of it that is clocked at 166 MHz. Besides its excellent performance, the 645 chipset is also benefiting from the fact that SiS has a P4-bus license agreement with Intel, making this chipset a real player without legal implications.

In order to compare the different platforms, we ran benchmarks on Pentium 4 systems based on all available chipsets. One question is particularly interesting: How does the i845 and i845D perform against the SiS645 and VIA's P4X266? Back in the times of 440BX and i815, Intel chipsets used to outperform its Taiwanese counterparts in terms of memory performance. Can i845D crush the DDR-competition?

Technical scheme of the SiS645 chipset.

These are the three available versions of the P4X266.