Hmmm so the BIOS isn't hiding any devices. Can you read the MTR registers from each of those target address decoders? for i in a b d c do for j in 0 4 8 do setpci -d 8086:6fa$i 0x8$j.L done done bit 14 is the IS_DIMM_PRESENT one. So you should see values like 001c5050 for populated slots. I see 000f000c for empty slots. -Tony [If you send me "lspci -xxxx" output I can check why the driver isn't reporting the 4th channel] -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html