Recording at 4K with a capture card on 1080p monitor

synnex_tv

New Member
Hello, I wanted to buy Elgato 4K Pro capture card to record my gameplay. Now, this is probably a stupid question, but can I actually record at 4K while playing at 1080p 144hz with this capture card or do I need a 4K monitor or dual PC system in order to do that? I've tried Nvidia's DSR, but that puts a toll on the GPU and I'm not even sure if the resolution recorded is true 4K, since my monitor's 1080p.
 

koala

Active Member
You don't need a capture card if you capture a game that is running on your PC as well as OBS. OBS is able to grab the video directly from the frame buffer of the game - nothing is more efficient. A capture card puts a higher load on your system.

To capture 4k, you need your monitor resolution as 4k. Otherwise the game isn't rendering in 4k. Nvidia DSR will work fine, because it cheats the system and tells it has a 4k monitor connected, so every game will create a 4k framebuffer and render in 4k. The monitor signal is scaled down to 1080p within the driver for the real monitor.

The toll on the GPU is what you will also see if you connect a real 4k monitor to your system, so with DSR it's a preview of the rendering load a 4k monitor will put on your system. The toll is not DSR-specific, it's 4k-specific. 4k resolution has 4 times the amount of pixels in comparison to 1080p, so it's up to 4 times the system load.
 
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synnex_tv

New Member
You don't need a capture card if you capture a game that is running on your PC as well as OBS. OBS is able to grab the video directly from the frame buffer of the game - nothing is more efficient. A capture card puts a higher load on your system.

To capture 4k, you need your monitor resolution as 4k. Otherwise the game isn't rendering in 4k. Nvidia DSR will work fine, because it cheats the system and tells it has a 4k monitor connected, so every game will create a 4k framebuffer and render in 4k. The monitor signal is scaled down to 1080p within the driver for the real monitor.

The toll on the GPU is what you will also see if you connect a real 4k monitor to your system, so with DSR it's a preview of the rendering load a 4k monitor will put on your system. The toll is not DSR-specific, it's 4k-specific. 4k resolution has 4 times the amount of pixels in comparison to 1080p, so it's up to 4 times the system load.

I see. But if I use DSR and put my monitor at 4K resolution and also set to record in 4K in OBS, will OBS record true 4K resolution of the game, like if I'm playing at 4K, while actually playing at 1080p? I don't want to change in game resolution to 4K. Just want to know if the recorded file will be in true 4K as if the game was running @4K on 4K monitor. Sorry for all these questions, but I've never messed around with this. I was watching Jackfrags and he was streaming at 4K while playing on his 1080p 240hz monitor, I thought he achieved that with a capture card.
 

koala

Active Member
I see. But if I use DSR and put my monitor at 4K resolution and also set to record in 4K in OBS, will OBS record true 4K resolution of the game, like if I'm playing at 4K, while actually playing at 1080p?
Yes, it does. Just try it yourself. If you analyze your recorded video and look for details only visible in 4k, such as pixel-thin lines, you will see it. However, it's a bit tedious to see with a 1080p monitor, since you need to make your media player play the video 1:1, showing only 1/4 of the whole frame, everything else is off-screen.

In the end, you have to set your game to 4k resolution to test it. It will also tell you if your computer is powerful enough to support that resolution. If it isn't, it's wasted money to buy a 4k monitor.
 

synnex_tv

New Member
Yes, it does. Just try it yourself. If you analyze your recorded video and look for details only visible in 4k, such as pixel-thin lines, you will see it. However, it's a bit tedious to see with a 1080p monitor, since you need to make your media player play the video 1:1, showing only 1/4 of the whole frame, everything else is off-screen.

In the end, you have to set your game to 4k resolution to test it. It will also tell you if your computer is powerful enough to support that resolution. If it isn't, it's wasted money to buy a 4k monitor.
Alright then. Thank you for helping me out with this. Cheers.
 
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