SCSI and ATA 66 hd performance question

[ModemMix]

i curently have a seagate cheetah 10,000 rpm scsi drive model number st39102lw its running on a tekram 390f scsi card right now that i plan to exchange for a DC-390 U2W on friday. I also have a quantum fireball 13cx ata 66 hd. Im running win 2k.

My question is... under hd tach 2.61 my scsi drive scores an access time of half that of the ata 66 drive, however the ata 66 drive scores near to twice the read burst as the scsi drive. The scsi drive isnt using all its features under the current scsi adapter, im just curious if these results are simply due to the scsi drive not beaing maximized because of the scsi card. or if i have some other more dasterdly issues.


The hd tack scores for the drives are below.
*******************************************
SCSI Seagate scores:

random access time 8.9ms

read burst speed 28.4 mbps

read speed -maximum 18803.0kps -minimum 4619.0kps -average 15585.0kps

CPU utilization 9.5%
*********************************************
Quantum Fireball 13cx:

random access time 19.9ms

read burst speed 46.1 mbps

read speed -maximum 19075.0kps -minimum 11341.0kps -average 16288.0kps

CPU utilization 8.9%
***********************************************************************


Aside from the access times it seems like the ide drive is out preforming my scsi drive..that just dosnt seem right, ill repost scsi results with the ultra 2 controler with lvd enabled, i hope its the scsi card not the drive i just got this drive back from seagate


ModemMix

 

[Pariah]

HD Tach scores under win2k seem to be a bit low for SCSI, not sure what causes it. Your SCSI card is an UW card with a maximum theoretical throughput of 40MB/s vs your ATA drive with a max of 66MB/s. Why would the SCSI drive have a higher burst rate? The Seagate numbers are still low even for win2k. The most important number, access time, is correct. That's all you should really worry about.

 

[ModemMix]

dou you think ill get better preformance with the scsi card that supports all the drives features? u2w and lvd?

 

[SunGoku]

IBM 75GXP series have very good sequential transfer rate. However, sequential transfer rate usually doesn't play a role as important as access time unless you do a lot of large block file copy/read/write such as copy your video files from one HD to another HD (and the HD has been defraged already).

SCSI excel in random access, especially under multi-task environment. EIDE/ATA's problem is only 1 device can be used at a time, not to mention just 1 command at a time. So, if you have your OS, game and all on the same HD, the performance might suffer.

The best use of resources (maximum benefit for the least amount of $$$) is do the following
OS, swap file, and important apps (including games) on a SCSI HD, preferably one with LVD such as Adaptec 29160, 39160 series or Tekram DC-390U3W. Apps which aren't used frequently as well as your data files can be stored on ATA drives. This give you the best of both worlds. You can take advantage of IDE's lower cost/GB as well as good sequential transfer rate for your storage needs and take advantage of the SCSI interface but very expensive/GB by putting all your OS and swap file on it, as well as important, often used apps on it.

Personally, unless wide range driver support is an issue, I would choose Tekram DC-390U3W. It uses LSI chipset so it's faster than the adaptec card, not to mention it's cheaper. I think if you use just the windows platform, there isn't much reason to choose adaptec over Tekram.

Another thing you need to in mind, the transfer speed from the outer rim of your platter is faster than your inner rim. Since your Seagate Cheetah 9LP is only 9GB, if you fill it up pretty well, it is going to impact the performance.

Read burst speed isn't important for the most part really, you don't need to worry about that number. What you need to worry about more is the access time, followed by the transfer rate as modern Windows environment will make use of access time the most, followed by the transfer rate.

Also, according to the seagate website, your HD isn't being utilized fully. Your current SCSI card supports only 40MB/sec while your HD is capable of 80MB/SEC ( http://www.seagate.com/support/disc/specs/scsi/st39102lw.html )

Generally speaking, except some mis-configuration/usage (i.e. bad driver or hardware, also empty or nearly empty ATA & full or nearly full SCSI HD), SCSI drives will beat ATA drives in access time but transfer speed is harder to say.

To solve your problem, get a Seagate Cheetah X15 like I did It has great access time and very good transfer time, fastest overall HDD on the market today I put all my old UW 7200 RPM SCSI drives onto my second system.