I am looking for a Threadripper-capable X399 motherboard for a video editing computer. I am looking specifically at two features, which I'm not clear whether they have or not:

1) I need to install a x16 graphics card, AND a Blackmagic video capture/playout card (https://www.blackmagicdesign.com/products) which requires a PCI Express 2.0 4x slot. Can I put the 4x capture card in one of the x16 lanes and have everything working at full speed? (i.e.: the graphics card working at x16, the capture card at x4...). And if I add in the future a second graphics card, can the motherboard accommodate all 3 cards at their full speeds? (the graphics cards at x16 and the capture card at x4).

2) All the motherboards I've seen support RAID using the onboard controller. But let's say I install 3 HDs, and I plan to leave one as stand alone (for documents and "regular" files) and set the other two as a RAID-0. Can any motherboard do that? (i.e.: set up a RAID array with only some of the existing drives, not all of them).


  • As for 1), I'm pretty sure, but don't know for 100% (because AMD's spec pages are shit) that these CPUs have 64 PCIe lanes, so they can easily take two cards at 16x and more memory / whatever at x4.
    – SEJPM
    Nov 12 '17 at 16:13
  • @SEJPM: sure, that's why I picked Threadripper as a platform. But I'm wondering if any of the existing motherboards have some... peculiarity in the way they organize their PCI slots, which can create some problem. The wording in some of the manuals I've downloaded isn't clear enough for me to be 100% sure.
    – PaulJ
    Nov 12 '17 at 16:29
  • 1
    There shouldnt be any peculiarities in organisition, but bear in mind that some lanes might be reserved for chips on motherboard (such as a USB 3 controller). As for RAID - the on board controller is waaay slower then dedicated ones. I recommend getting a small SSD for your current project and an HDD or NAS for archiving - that would be faster than on-board RAID. Nov 13 '17 at 12:41
  • @Jan Dorniak: Mmm... when it comes to video editing, a "small SSD" won't do to hold the footage ;-), and an external NAS will be too expensive. This leaves a dedicated RAID card. The problem is that, from what I see, that market has pretty much died. Do you have any recommendations on that front?
    – PaulJ
    Nov 13 '17 at 20:39
  • "Small SSD" as in 256 GB :) As for dedicated RAID cards - I'm almost certain the market isn't dead, just that from the very beginning it was an enterprise product. As for speeds of on-board RAID - I've got two 8 years old WD Blacks in software (on-board) RAID 0 using Intel H97 and I just measured roughly 210 MB/s read and 140 MB/s write speed. Nov 13 '17 at 20:56

Asus PRIME X399-A

This does support RAID 0,1, and 10 However RAID 1 is kind pointless especially if you use SSD.

Right from the manual


And it supports 2 ssd of the m.2 variety.

enter image description here

You can put any size card in an x16 slot. However, note 2 of the x16 slots operate in x8 mode, but that is still more than x4 card needs.

Lets forget the RAID at least for speed. The M.2 SSD can clobber any expensive raid. https://www.bhphotovideo.com/bnh/controller/home?A=details&O=&Q=&ap=y&c3api=1876%2C%7Bcreative%7D%2C%7Bkeyword%7D&gclid=Cj0KCQiAv_HSBRCkARIsAGaSsrBf8KGzl6AJd8odxhLmOkT4PiP4B0gpyKEU5EvVg36xr7F-HVn733caAuGDEALw_wcB&is=REG&m=Y&sku=1288028

Sequential Read Speed Up to 3,500 MB/s Sequential Write Speed Up to 2,100 MB/s

It will take 10 extremely fast hard drives to even match the write speed. This is about equivalent to 4-7 regular SSD.

  • How is RAID 1 pointless? Did you mean RAID 0 would be pointless because the SSDs are fast enough without striping? I can't imagine how redundancy would ever be 'pointless', unless you don't need redundancy. Also "M.2 SSD can clobber any expensive raid." - wut? no. If you RAID 0 the M.2 SSD's you get 2xs the speed! RAID is NOT implicitly HDD. Feb 12 at 18:55

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