SiS 645DX Reference Board (1)
Overclocker 4 March 2002

SiS645DX

We have seen many reviews of the SiS645 on the net. Today we bring you an exclusive of the latest chipset - the SiS645DX. SiS645DX is the new generation of the SiS645. SIS645DX supports the official 533Mhz standard e.g. those P4 that runs 133Mhz (533) FSB. Secondly, the SiS645DX officially supports the DDR333 standard. While lots of people thought DDR333 means running the CPU at 166/166 (333/333), that is not true as it is considered overclocking. In fact, it should be async 133/166 (266/333). To our surprise, SiS645DX has something even better which we discovered in the BIOS. The BIOS allows us to run the board at Async DDR400 mode. That means running the DDR module at 400Mhz (not 266, not 333)! Although P4 533Mhz CPUs are not available at this moment, we can always use a P4 ES by lowering the multiplier. In our tests, we lower the P4 1.5G's multiplier to 11x and raise the FSB to 133Mhz. We also tested the mainboard at various combinations of mode. e.g. synchronous 133/133, async 133/166 (DDR333) at Ultra timings and 133/200 (DDR400) at fast timings.

This picture below is the SiS645DX reference board. We have more photos on the next few pages.

Next

(C) Copyright 1998-2009 OCWorkbench.com