scsi tape drive slow in freebsd

[Frank Mancuso]

hello there I have a scsi tape drive which is made by seagate python.
It is a scsi 2. normally in linux or windows it takes about 2 hours
and 30 mins to restore or backup. I just installed freebsd 4.11 and I
started to restore and it has been running for more then 10 hours ..

this is my dmesg

ahc0: port 0xe800-0xe8ff mem 0xe1811000-0xe1811fff irq 11 at device 12.0 on pci0
aic7860: Ultra Single Channel A, SCSI Id=7, 3/253 SCBs
Waiting 15 seconds for SCSI devices to settle
sa0: Removable Sequential Access SCSI-2 device

I had to recompile the kernel to support my dual P3 I was wondering if
maybe I had to add something in the kernel to speed this up..

thanks.