Why cann't I read SPD for SiS 745 chipset?

[Charlie Song]

Hello,   I'm trying to read SPD of DIMM on a motherboard with SiS745 chipset. But I cann't read it. I've checked the ACPI enable bit. It is 0xD8. The ACPI Base Address is 0xE400.   Can anyone help me to fix the problem ?   Thanks,   Charlie