I have recently installed a new HDD as I expanded from 2 to 3 cams. I have noticed when checking some playback (Seems to be when there is more movement) but the video either seems to jump a fair few seconds missing footage, or recently I just checked one piece of footage & it jumped back 3 - 4 seconds & continued to play. Im back on standard H264 & can see no reason for the playback to become jumpy every now and then