KR7A-R can boot up with ECC memory modules installed, but without ECC function.
It supports up to 3GB of un-buffered memory and 4GB of registered memory. Please mention that the maximum DDR memory support of KR7A is about 3.5G rather than 4G. This limitation is caused by PC architecture and the missing 0.5G memory address is reserved for PCI I/O space, AGP aperture mapping space and other onboard device I/O space, so, although the KT266A datasheet exclaims the memory support is up to 4GB, actually the system only use about 3.5GB with four 1G DDR memories installed. In another word, BIOS and operation system will report about 3.5GB only.
Please refer the FAQ: http://fae.abit.com.tw/eng/faq/qa/2001/2001121102.htm