NVIDIA has reportedly increased the concurrent sessions limit of its NVENC hardware video encoder on GeForce graphics cards to 3, up from 2. This means up to three different apps could use NVENC simultaneously, or an app (such as Premiere Pro) could use up to three sessions of NVENC for faster live previews during video editing. NVIDIA's Quadro family graphics cards can have practically unlimited NVENC concurrent sessions. The company recently updated the NVENC support matrix page showing a "Max # of concurrent sessions" increase from 2 to 3. The first screenshot below shows the updated page, and the second one shows a Web Archive snapshot from 2 weeks ago. NVIDIA last updated its GeForce drivers late May with 446.14 WHQL, so you might want to update your drivers.