Playback issues with large rosbag files

Hi, I'm running into issues playing back large rosbag files (> 1GB, they are bags generated of the KITTI dataset using this tool https://github.com/tomas789/kitti2bag for those that are interested). The overall performance (particularly the tf) performance varies greatly, and is particularly poor the first time the bag is played. I suspect that the bag needs to be loaded into memory / cache for proper behavior. I am playing the bags using sim time set to true and the clock option for rosbag play (the issues remain with the options off too). Does anyone have ideas about the causes and fixes/workarounds? Thanks!