This is likely not a tape issue.  52GB/hr is about 14.8MB/sec.  I am betting
your disk cannot read the data any faster than that.  Unless the data is not
compressable at all the typical rates for a SCSI Magstar drive are 25+MB/sec
and can get as high as 34 on Ultra SCSI if the cables are real short.  Fibre
Channel easily gets 33.  What kind of disk is the source?

Paul D. Seay, Jr.
Technical Specialist
Naptheon, INC
757-688-8180