UEFI, BIOS, and new video cards

Recently I've heard that the new rx400 series of AMD cards only supports motherboards with UEFI. First, is there any definite source on this? Do new nvidia cards also only support UEFI motherboards? when did this start?

Today is the first I've heard of anything like this, so it would be good to know if it's actually true.

Where did you hear this? Do you have a link?

I was talking with a friend who got an rx460, didn't work on his motherboard, a relatively new asus m5a78 whatever it was. Anyway, according to him support with standard Bios boards like his is iffy. However, that claim is only really backed up by what random people like us are saying on forums. Real sources are kinda what I'm looking for.

They have code for UEFI but if you set the BIOS to legacy mode on older motherboards with early UEFI support that can sort the non-boot issues. One side affect is not seeing any boot screens until Windows loads.

They should work with pre-UEFi boards with basic VGA boot code but it will depend on the BIOS code on the GPU.

I've got several RX 470/480 GPUs of a couple a brands and most work fine but put one in an incompatible system (RX470 Nitro+ & Gigabyte Z77 mobo for example) and all you get is a blinking "-" sign in the top left until the legacy BIOS mode is enabled.

The naughty card is in the middle :)

It's so naughty it works fine with the "Turbo" BIOS but won't boot with the "silent" BIOS (dual BIOS Nitro+) until the legacy mode si enabled.

So any given card may or may not work based on what the manufacturer did with the video card's Bios. An asus could work while a sapphire card might not while both being rx460s for example. Weird.. then you'd have to verify that it works beforehand from someone else/the manufacturer before purchase. Otherwise it's a gamble. That's really interesting, thanks for your reply.

Yes it's not a major problem but it does happen. I think we would see a recall situation if it was that widespread.

Most of my GPUs are open box or B grade and I thought I'd got a duff Nitro+ until I read you could enable the legacy motherboard mode plus it was in the silent setting when i received it. Switching to the turbo would also have fixed it but I use the silent position for my low power mining BIOS.

Plus, the people getting these cards are gonna almost always have a relatively new system with Uefi (I'd assume). Not many people use plain old Bios computers.

i have uefi /bios and i only boot into bios mode. but i am running win 7. funny enough i have never had a uefi OS installed.