How to choose a capture card
Two numbers get confused constantly: what the card records, and what it passes through to your monitor. A card can pass 4K120 to your screen and record 1080p60. Check both, separately, before buying.
Internal or external
Internal PCIe cards have lower latency and no USB bandwidth limit, and need a free slot in a desktop. External USB cards work with a laptop or a console and are limited by the USB link. For a two machine streaming setup, external is usually the right answer.
Host interface is the real ceiling
USB 3.0 at 5Gbps is enough for 1080p60 uncompressed or 4K30. 4K60 uncompressed needs more, so most 4K60 external cards compress on the card. Plugging a 4K card into a USB 2.0 port silently drops it to a fraction of its capability.
HDR and high refresh rarely combine
A card advertised as 4K60 HDR often cannot do 4K60 and HDR at the same time, or drops chroma to 4:2:0 when both are enabled. If you play HDR on the passthrough output, confirm the exact combination is supported.
Hardware or software encoding
Cards that encode on board take the load off your CPU, which matters on a single machine setup. Cards that hand raw frames to the host give better quality and need a capable CPU or GPU encoder.
Latency on the passthrough
Passthrough delay is invisible for talking head recording and very noticeable in fast games if you play on that output. Low single digit milliseconds is fine.
Common mistakes
- Buying to the passthrough number and discovering the capture ceiling is lower.
- Using a cheap HDMI cable at 4K, which produces dropouts that look like a faulty card.
- Forgetting HDCP. Console and streaming service output may refuse to capture.