Performance gains with SCSI HD ?

[Tanj]

I've been trying to gather information on SCSI interface, and I get conflicting messages.

I've always believed SCSI to be faster than IDE. But apparently, whereas even older IDE can support up to 33Mb/sec (UDMA or ATA-33), only high-end SCSI cards (Ultra Wide SCSI and above)can support faster tyransfer rates. The more standard (older) Ultra SCSI can only support 20Mb/sec. Not such a good deal, it seems. On the other hand, as I understand it, SCSI HD are far more capable of filling-up the interface capacity than IDE drives.

Does this mean that it's better to get a SCSI card & HD (lower theoretical transfer rate but actually uses it fully)then and IDE HD (faster transfer rate with UDMA but the drives themselves don't actually use that full capacity) ??? I probably got it wrong, and would appreciate some guidance. My dilemna is that if I can pick-up a cheap SCSI card/HD (I have an old system), will there be any performance gain over my existing UDMA-33 4Gb 5200 rpm IDE HD ? Sharky's pages seem to say 'nay' - its only good if you're going to run multiple devices on the same interface. Day to day performance gains for a HD is negligible.

Whaddayathink ?

[Warthog]

Seem to be following you around....

Here is my very, high end, technological expertise about scuzzys:
They go at 10,000rpm
http://www.sysopt.com/forum/wink.gif
Warthog

[big_block_buick]

i was thinking the same thing a little while ago, i had seen a good deal in user to user.and thought why not.only newer scsi drives go 10,000 rpm.all the people i talked to led me to believe unless i was to go high end scsi,an ata66 drive would be better..maybe someone who has one will give you some more info..

[CMonster]

For average home use I would recommend an IBM Ultra ATA 100, 7200rpm drive, these drives have excelent performance and best value for the money. Although SCSI is very reliable, fast, uses low CPU overhead, and can far exceed the number of drives the IDE interface can support, most home users do not need SCSI.

Just for comparrison:

IBM 30GB Ultra ATA-100/7200rpm drive ($149) -IDE interface adapter is built in to most modern motherboards

9GB Ultra SCSI-160/7200rpm drive ($239) -adapter costs between $200-$300

The speed of both drives for day to day applications is almost the same.

edit: note- don't be decieived by labels like "Ultra" and "33/66/100MB/s" or "160MB/s" these refer to theoretical maximum burst rate and not the actual sustainable transfer rate of the drive -which in every case is much lower.



[This message has been edited by CMonster (edited 04-14-2001).]

[NDC]

I agree with CMonster that IDE drives are usually more than adequate for general home users. SCSI 10,000rpm or 15,000rpm hard disk drives are faster since the disk rotation speed surpasses IDE max speed which is 7,200rpm nowadays. But most noticeable difference is shown in heavy disk access environments such as graphics, Audio Editing, Video Editing etc... SCSI hard disk drives. Another advantage is that SCSI drives have less CPU utilization since it's controlled by the SCSI controller. SCSI hard disk rely less on the CPU get the job done. SCSI supports a feature called command-tag queuing. Command-tag queuing lets disks efficiently handle multithreaded applications that issue multiple disk commands.

The downside to SCSI drives are definetly the high price and that it requires a high-end SCSI adapter to take full advatage of a high-end SCSI hard disk. You would need to buy an Ultra 160 SCSI Adapter to run a SCSI 10k or 15k Ultra 160 hard disk at it's full performance.

As for convenience on SCSI interface drives is that you can connect up to 15 devices on a single channel or 30 Devices on 2 channels. It also has internal & external LVD channels that you can connect legacy devices so that it won't slow down the faster devices on the same chain. If you have many devices that need to be daisey linked, SCSI is very convenient Vs. using IDE interface which allow up to 4 IDE devices on two IDE channels or up to 8 IDE devices if you a have mass storage device controller that is PCI interface or on-board which I think should be more than enough expansion room for most users...

[This message has been edited by NDC (edited 04-14-2001).]

[Stan]

Ditto CMonster...

Buy yourself an IBM 75Gxp or 60Gxp (new series). They are fast, reliable and way cheaper than SCSI HD.

If you want good performance, you can buy 2 IBM and a RAID IDE controller (from Promise).
I don't how much you want to spend on your PC, so it is up to you.
Unless you do heavy 3D apps or have lots of $$, SCSI is not for you.

Stan

[Warthog]

I have a 45gb IBM 75Gxp drive. I couldn't be happier http://www.sysopt.com/forum/smile.gif

Warthog

[Tanj]

Great feedback - I think I'll stay away from SCSI. I also think that I'm due for a #%@$*#$ upgrade of my mobo/CPU, but I wanna squeeze everythin' out of my existing one. I'm just so cheap http://www.sysopt.com/forum/wink.gif