Currently I am trying to assemble a sequence and am experiencing terrible playback performance. Timeline is set to 1920 x 1080 and 1/4 resolution. Footage is a mix of all-I .mxf from 2 Canon C70s and relatively low bitrate H.264 from a C100 MKII. Activity monitor shows very low GPU utilization, is there a way to fix this? Perhaps a setting I am overlooking? Have tried uninstalling and reinstalling premiere with no change. All footage is stored locally on the internal SSD.