As far as I have seen, there is no "IDE or AHCI" setting in BIOS. From one HD to another in windows is ~20MB/s, in Linux it is about 12MB/s.
I did see that "bus mastering" was turned off, though. Turning this on did improve things. Windows now sees ~35MB/s rates, and that is Win2k not XP.
[root@localhost root]# hdparm -tT /dev/sdb
/dev/sdb:
Timing cached reads: 1654 MB in 2.00 seconds = 826.88 MB/sec
Timing buffered disk reads: 266 MB in 3.02 seconds = 88.01 MB/sec
[root@localhost root]#
But...
[root@localhost Linux]# dd if=/mnt/1t/File\ bin/ISO\'s/Linux/lucid\ puppy\ 5.25.iso of=/root/deleteme.bin
261548+0 records in
261548+0 records out
133912576 bytes (134 MB) copied, 5.27582 s, 25.4 MB/s[root@localhost Linux]# dd if=lucid\ puppy\ 5.25.iso of=deleteme.bin
261548+0 records in
261548+0 records out
133912576 bytes (134 MB) copied, 24.6866 s, 5.4 MB/s
Why is there such a speed difference, and why is transferring to a slower PATA drive that much faster than copying back on the drive?