This card. Avermedia GC571 Live Streamer Ultra HD 4K UHD.
The user manual is skimpy. It has HDMI in and out. But do I have to use these? I wish to record the horrible time lag my internet is suffering. So I want to just record the screen as I attempt to load various pages. Can I just record my screen without having to route my graphics card output into the HDMI input and then out to my monitor? Or is there an option to just capture the video output through the PCI bus? Skipping the in/out cabling? My video card and monitor have DP ports. Nice if I could avoid a gender bender cable purchase. I need to get this evidence to lodge a solid complaint about my crap service. And after that is done, to capture various lurid video for fun.
First: I have never used the Avermedia GC571. I doubt many here, if any, have used this. I did a search. I know this is FQ but not sure how else this can be answered for such a niche product.
That said, near as I can tell, this absolutely needs and HDMI cable (it says it comes with one). It is made to capture from external sources. Not from your internal PCI bus.
If you want to record your screen showing internet lag while browsing try OBS Studio (free).
I could be wrong of course and/or may be misunderstanding what it is you are trying to do. Hopefully others will chime in.
As @Whack-a-Mole says, if all you want to do is record your screen, you can use OBS Studio. Just set it up to record locally with your primary monitor as the capture area (or just your web browser if you would rather focus on just one app). It will create a video file locally you can use to verify your performance.
There should be no reason to use a video capture card unless the source is something external to your computer (e.g. a video camera).
If you happen to be using a Mac, it’s even simpler as window recording is built in to the OS along with the Screenshot tool.
What they said. You don’t need special hardware to record your desktop. You don’t even need OBS, necessarily. Windows key + S should launch the snipping tool and let you record it: How to Record Your Screen on Windows 11 | Microsoft Windows
(Edit: Actually, seems like the snipping tool only records in Windows 11, so on 10 you might still need OBS or similar)
Those cards are for recording things like gaming consoles for streaming. They won’t do you any good for just recording your own computer.