Encoding lag is only happening when you're encoding @ 2.5Mb/s. @ 4.5Mb/s it looks good but the test was only like 30 seconds.
8:43:44.133: [jim-nvenc: 'advanced_video_stream'] settings:
18:43:44.133: codec: H264
18:43:44.133: rate_control: CBR
18:43:44.133: bitrate: 4500
18:43:44.133: cqp: 20
18:43:44.133: keyint: 60
18:43:44.133: preset: p4
18:43:44.133: tuning: hq
18:43:44.133: multipass: disabled
18:43:44.133: profile: high
18:43:44.133: width: 1280
18:43:44.133: height: 720
18:43:44.133: b-frames: 0
18:43:44.133: lookahead: false
18:43:44.133: psycho_aq: false
18:43:44.133:
18:43:45.069: ---------------------------------
18:43:45.071: [FFmpeg aac encoder: 'adv_stream_aac'] bitrate: 160, channels: 2, channel_layout: stereo
18:43:45.071:
18:43:45.084: [rtmp stream: 'adv_stream'] Connecting to RTMP URL rtmp://lhr04.contribute.live-video.net/app...
18:43:45.161: [rtmp stream: 'adv_stream'] Interface: Killer E2400 Gigabit Ethernet Controller (ethernet, 100 mbps)
18:43:45.812: [rtmp stream: 'adv_stream'] Connection to rtmp://lhr04.contribute.live-video.net/app successful
18:43:45.814: [rtmp stream: 'adv_stream'] Socket send buffer is 65536 bytes
18:43:45.887: ==== Streaming Start ===============================================
18:44:17.299: [rtmp stream: 'adv_stream'] User stopped the stream
18:44:17.299: [rtmp stream: 'adv_stream'] Socket send buffer is 65536 bytes
18:44:17.300: Output 'adv_stream': stopping
18:44:17.300: Output 'adv_stream': Total frames output: 923
18:44:17.300: Output 'adv_stream': Total drawn frames: 967
18:44:17.311: ==== Streaming Stop ================================================
18:44:17.396: warning: 2 frames left in the queue on closing