True 4K capture requires significantly more bandwidth than 1080p — and most capture cards compromise. USB 3.0 caps out at around 5Gbps, which is borderline for uncompressed 4K30. For 4K60, you need either USB 3.2 Gen 2x2 (20Gbps), PCIe, or a hardware encoder that compresses onboard.
The practical question is: do you need 4K on the capture card, or 4K in the output stream? Most streaming platforms still deliver 1080p to viewers — so capturing in 4K gives you headroom for cropping and post, but the viewers may not see the difference.
Use our Product Selector — answer a few questions about your camera, software and resolution, and we'll recommend the right Magewell model.