我目前的主板的PIC-E是2.0的
我打算用3個HDD架RAID5,頂多以後用到6個HDD,
剛才在tomshardware看到,2個回覆是這樣寫

The 4x slot is it as large as the 16x slot.


Since you said you were worried about data loss, you will be using either RAID5 or RAID6 which means your array likely won't be pushing more than ~6Gbps, about a third the x4 slot's bandwidth. So unless your controller has a quirk that makes it require a x8 slot for operation, there should be no problem with using x4

所以把PIC-E 8X的卡裝在16X的槽中,以4X工作沒問題
只是如果HDD太多時,可能會被4X限制住,
但對我來說只有6個HDD,應該還沒到PCI-E2.0 4X的上限

另外請教PCI-E2.0 4X的頻寬是多少,在WIKI看的有些眼花,看不出來2.0 3.0的數據