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my 15k rpm scsi setup is SLOW!!! please help me get it up to where it should be

C

cirthix

Diamond Member
adaptec ultra160 card and the drive is a seagate cheetah 15.3k, ultra 320, 18gb

the problem is that sisoft sandra shows the drive as having a "17mb/sec drive index" and it doesnt seem fast. any settings i can change? There are some jumpers on the front of the drive, but i don't know what they do. i had this problem with another, older, controller too. i checked in the scsi card's bios and it is indeed operating at u160 connection speeds, so i think its the drive. auto-termination is being used, and results don't change with the terminator being on or off.
 
17 MB/s smells like either asynchronous transfer mode or single-ended-narrow sync transfers. Both would be caused by improper cabling and termination - so check that.
 
Originally posted by: bacillus
do you have a terminator at the end of the lvd cable?
Click to expand...
Originally posted by: cirthix
auto-termination is being used, and results don't change with the terminator being on or off.
Click to expand...



using auto-termination with no terminator at the moment
i ran sandra wth auto-termination on and a terminator
 
You definitely need a terminator at the end of the cable. Go look up the drive's spec sheets at seagate.com and see what those jumpers do, maybe some of them should not be in use.
 
the only jumpers on the drive, jp6 according to the manual, are not discussed there. i have the lc version, with the sca 80 pin connector. would an sca->68 pin cause this performance loss? i have the same results with and without the terminator, but i'll plug it back in anyway
 
If the SCA-to-68 adapter isn't LVD capable, it'll drop you back to at most 40 MB/s (single-ended UW). Similarly, the terminator on the far end of the cable must be LVD capable to let this SCSI branch run at U2W or faster modes.

To make it clear: There ain't no debating the termination. Card termination on AUTO, far end of all cables terminated.
 
You need a proper cable too - usually you can get an LVD cable with a terminator at the end for under $20. on eBay or elsewhere around the web. Everything must be at least LVD, U160 rated to get optimum performance. That means SCA to 68-pin adapter, cable and terminator. Once you get that straight, you should start getting the speed you paid for.

.bh.
 
Originally posted by: Peter
AND the cable.
Click to expand...

just googled the calbe i have, looks like its ultra320 compatable. amphenol spectra strip 68pin scsi u320 4 device cable. i'll look into the sca adapter, as zepper said
 
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