Low Download Speed with Significant Amount of Corrected/Uncorrectables

I replaced the coax from the line into the house and checked that all connections are snug.  There's a splice connection at the drop into the house, but I can't replace that.  Otherwise, it's a straight shot from the drop to the cable modem.  The problem still persists; low download speeds, but upload speeds are fine.  Guess I'm going to have to have a technician out.