嗯！感謝。

和我想的一樣，後來我找了一下相關資料，確定ALI的Chipset的確就是8bit/16bit。
不過還是很奇怪，怎會有8bit/8bit的情形呢？

HyperTransport Technology (HTT) I/O Link
• HyperTransport Technology I/O Link Protocol Meets the v1.05 Specification
• 16-bit HTT downstream link & 8-bit upstream link @ 800MHz
• HTT supports transfer rates of 1600, 1200, 800, and 400 mega-transfers per second.
• Maximum bandwidth is 3.2 gigabytes per second downstream and 1.6 gigabytes per second upstream
• Independent transfer rate and bit width selection for each side.
摘錄http://www.ali.com.tw/eng/products/...l.php?pserno=57