PCIe 16x card in PCIe 4x slot?

[Rhinox]

My motherboard has only one PCIe 8x (now used by raid-controller) and a few PCIe 4x slots, and I need graphic card (passthrough to VM). Now my question is:

If I manage to fit PCIe 16x graphic card into PCIe 4x slot, will it work? All I need is GFX with "symbolic" DX11-support, with no extra performance required (only 2d). It is very difficult to find PCIe 4x/1x card, but I have a few PCIe 16x lying around...

I know a little hardware "tweaking" would be necessary: I'd have to cut open back side of PCIe 4x connector on mobo so that graphic card could protrude from connector (or cut part of graphic-card interface, but that's for sure more dangerous)...

 

[lucidrenegade]

If you go the riser cable route, I would get an x4 to x16 cable if you are using an x4 slot. You're perfectly fine using an x1 to x16, but you might as well get as much performance as you can.

 

[JSchuricht]

Most of the time it works fine but some mainboard/video card combos won't see a 16x card in a 1x or 4x slot due to the PCIe presence detect not functioning. To get around that you will need to short A1 with B17 on the PCIe slot.

 

[Terry Kennedy]

Absolutely. it will even work wonders.
New PCI-E PCI Express x1 To x16 Adapter Extender Cable Riser Card

The blue painter's tape used as an insulator adds a nice touch.

 

[Diavuno]

I have done it several times... works fine,

even as I type this from my desktop I'm pushing 2x ATI cards each in a 8x slot.

 

[DavidRa]

You could also consider a simpler PCIe x1 card like this ATI-based one, if your required performance fits in the envelope. Saves slicing the end of the slot open ...