So I built myself a new rig...

[Calinou]

Disable PCI-E 3.0 (and use PCI-E 2.0 instead) in the UEFI? There won't be any performance decrease, especially considering how the 290(X) is crippled under non-Windows OS...

[Kano]

For Kanotix gfxdetect mode it is not allowed to have Intel active. In that case i do not activate fglrx. Certainly i would use something i know that works, if it does not it is a driver fault. From usb key you can start Kanotix in uefi and mbr mode.

[FutureSuture]

I had a very similar issue when I attempted to test a discrete GPU with Linux in my APU build. IIRC, the bios had some dual-GPU mode set by default and I had to switch it to auto for Linux to boot properly.
I hate it when something is caused by an incorrect BIOS configuration :/ IIRC, the option was hidden and at the very end of all the configuration options on my ASRock board, too

The thing is, my monitor is already connected to the GPU, and shows me everything up until the blinking underscore. Why would the CPU suddenly be a problem? And why is it not a problem only when booting the nonfree driver in UEFI mode?

[FutureSuture]

As you did not find it, I even downloaded the manual of your board. Guess what, you can find the setting in the Peripherals section:

Internal Graphics - Disable (or Auto if available)

Hard to believe that you did not see that...

Oh, that? I already tried that and it did not help whatsoever. Please stop being so condescending. Thank you. I am looking for help, not accusations.

[Ouroboros]

I had a very similar issue when I attempted to test a discrete GPU with Linux in my APU build. IIRC, the bios had some dual-GPU mode set by default and I had to switch it to auto for Linux to boot properly.
I hate it when something is caused by an incorrect BIOS configuration :/ IIRC, the option was hidden and at the very end of all the configuration options on my ASRock board, too

[Kano]

As i do not own Optimus i tested radeon+Intel, radeon+nouveau successfully, but i could not fake real Optimus with binary nvidia driver. 2 or more cards from the same vendor did not work as well. For nouveau i needed an override to init it with Intel first and kernel 3.13. Vdpau can be switched with PRIME, vaapi needed a patch. I got am hotfix for vaapi but it crashes inside the app still when you use a non supported card with it. Nouveau does not work on a system without CSM, can not test this with radeon as i only have got old Evergreen cards. But binary drivers do not really work well on Desktops when Intel onboard is active, even when no monitor is connected.

[DanL]

Which would be like an Optimus setup. Don't enable Intel GPU in your firmware when you don't know what you do. I guess Gigabyte has it as default as somebody with Nvidia GPU had the Intel GPU active as well with a Z87 board...

Just having an integrated and discrete card does not make it a hybrid GPU setup...

A discrete PCI-e card should automatically disable the integrated graphics on most motherboards.

[Kano]

As you did not find it, I even downloaded the manual of your board. Guess what, you can find the setting in the Peripherals section:

Internal Graphics - Disable (or Auto if available)

Hard to believe that you did not see that...

[FutureSuture]

It's simple why i wanted the full output. You see this:

00:02.0 VGA compatible controller [0300]: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:0412] (rev 06) (prog-if 00 [VGA controller])

and

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Hawaii XT [Radeon HD 8970] [1002:67b0] (prog-if 00 [VGA controller])

Which would be like an Optimus setup. Don't enable Intel GPU in your firmware when you don't know what you do. I guess Gigabyte has it as default as somebody with Nvidia GPU had the Intel GPU active as well with a Z87 board...

Ahhh, I see what you mean now. I don't see how that happened, though. On my old desktop (built it myself too), I had an Intel CPU and a Nvidia GPU and never had that issue with booting live USB sticks. Is there a way to disable the Intel GPU in the UEFI? I haven't been able to find a way yet.

[Kano]

It's simple why i wanted the full output. You see this:

00:02.0 VGA compatible controller [0300]: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:0412] (rev 06) (prog-if 00 [VGA controller])

and

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Hawaii XT [Radeon HD 8970] [1002:67b0] (prog-if 00 [VGA controller])

Which would be like an Optimus setup. Don't enable Intel GPU in your firmware when you don't know what you do. I guess Gigabyte has it as default as somebody with Nvidia GPU had the Intel GPU active as well with a Z87 board...