dual PCI-E riser cards
 

Hi for a project I've been working on using 4 monitors I've been using 2 Nvidia cards on a dual PCI raiser card. However as this hardware becomes more difficult to get I'm thinking of changing to PCI-E based cards. Can anyone advise if this is possible? I presume it will just work exactly like a PCI rieser but an unsure if there are any other issues.
So can anyone advise can I use a dual PCI-E riser with Etch? And any you would recommend? Thanks :)