386GT Adaptec SCSI performance :-(

[Larry Pajakowski]

We recently put an ADAPTEC 1540A SCSI into a Compaq 386/20 as a second disk
controller using 2.3.2GT.  The first contoller is the Compaq supplied WD1007.
Performance on the SCSI disks are worse (I'm being kind) than were expected. 
Here are some performance numbers all in kb/sec.:

	disk		raw device	block device	large file

	ESDI		340		319		288

	SCSI		107		 57		 56

The ESDI is a Compaq supplied 300mb Minisribe and the SCSI disks (2) are CDC
Wren IV also 300mb.  The ESDI file system is fairly new and the SCSI file
system is virgin.  BTW the correlation of block device to large file is worth
noting in light of the benchmarks published here a week or so ago.

I tried reformatting with adfmt but got an error.  Also the 1540A was jumpered
for both sync and async negotiation with no change.

Anybody have any ideas?

Thank's


Larry Pajakowski
...ddsw1!tapa!larry