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ATA versus SCSI

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I apologize in advance for this topic. I'm sure it has been introduced in this forum umpteen times. But with money becoming increasingly tight ( I am a grad student) I must make the choice--SCSI v. ATA.

I am a long time Mac user, very familiar and comfortable with SCSI. I am currently running a Maxtor 10kII off of a Adaptec 2940UW. I like it very much. I also have an external array of two IBM 7200 UW SCSI drives.

I just purchased a G4 500MHz (Sawtooth). My plan was to run the system and apps on a ATA drive, maybe the newer IBM 7200 40Gig. In addition, I was going to add a two drive array consisting of two Maxtor 10kIIIs and the Adaptec 29160 ($270x2 + 300 = $840).

I am planning to do video work. I purchased an Aurora Igniter = MJPEG compression at 1.5:1 or upto 13MB/s.

Is SCSI sill worth the investment??

Any thoughts would be greatly apprechiated.

Alex

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I think that one of the first questions I would ask you is "Is the 13 MB/s for one stream of video or more than one stream?"

If it is just one stream, then you would probably be alright with a single ATA/IDE drive without RAID. If it's more than one stream, then RAID will definitely help.

I think that nowadays, besides price being the big difference and the history between ATA and SCSI, I think (from what I"ve read so far) that the biggest difference between the two now is size of the drive, rotational speed, which in turn, affects access/seek times. That seems to be a really big thing nowadays since besides, that, there hasn't really been much improvement or actual innovation going into the drives. (Though I personally think that the IBM drives with the ramp load/unload is a VERY good idea).

I don't know....I don't really have much experience with RAID or SCSI (cept my ONE SCSI drive right now)...so I can't really say (also especially for a Mac system, cuz I'm sure that you might have come across the huge thread about the terrible SCSI performance under Windows XP.)

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One thing I would suggest is to forgo an Adaptec at $300 and get a Tekram dual channel retail box with cables and terminators for $200 or less.

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What do you mean by video work?

Even 5400RPM ATA drives can handle 13MBps... If you intend 1-time capture at max qual b/c you have no timecode then realize edits and moving around a timeline with media on an ATA drive can be jerky/not as snappy as SCSI. Renders also take longer due to ATA overhead.

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the 13.3 MB/s will be for one stream. the igniter video card in not a "realtime" card. so rendering and compositing will be done in premier/fcp and after effects, pulling multiple streams off the array--but of course, the CPU will be the bottleneck.

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CPU usually is...

With multiple streams, ATA drives will likely tie up the CPU even more than normal. One stream per ATA w/drive per channel may help. But low seek SCSIs should be worth 1K$ if your work is not a hobby. Should shave off a considerable amt of time. Otherwise I'd use SCSI boot/virtual mem/scratch/destination/etc and probably (off-hand) well-cooled IBM 120GXPs for sources.

I've no experience with WD's JB's though ...

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If you're only processing/compiling one stream of video at a time, then you would be able to do it with one drive, alone (preferably two, one to read, one to write) no problem.

If you're doing any more streams than that, than....alternative methods may be requied so that no frames get dropped in the process.

I've never really tired having two or more streams, but...I would probably recommend SCSI for writing it (since it would be smaller due to compression - or I would hope so) and then the IDE drives for reading since in Windows XP, SCSI drives don't perform very well.

At least that's how I have my system set up right now, and it processes 5 streams, one after another though. Raw data rate is about 4.5 MB/s (320x240, 24bpp, YUV Native, off cable TV). For me, 43 minutes of a TV show is about 11.0 GB, and I end up compressing it down to about 245 MB with Adobe Premiere 6, MPG42 (Microcrap MPEG-4 Codec V2) 1742 kbps, 75%, keyframe every second, IMA ADPCM(SP?) Audio, 22kHz, 16 bit - stereo).

But I haven't really ever mixed multiple streams together though.

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Guest russofris
CPU usually is...

With multiple streams, ATA drives will likely tie up the CPU even more than normal. 

I've no experience with WD's JB's though ...

ATA CPU Utilization is a function of the Controller, it's BIOS, it's driver rev, and the model of drive being used. Generally speaking, ATA CPU utilization is higher than SCSI.

In reality, a properly configured system should display little to no difference in CPU Utilization when compared to SCSI.

I would recommend that we (SR Community) should investigate this area a bit more thoroughly in the future, and report our Min/Max/Avg CPU utilization when posting our benchmarks.

Perhaps we should start a "Benchmark Results" forum like 3Dmark has, and have predefined criteria for the user to fill in.

Thank you for your time,

Frank Russo

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I would recommend that we (SR Community) should investigate this area a bit more thoroughly in the future, and report our Min/Max/Avg CPU utilization when posting our benchmarks.

Perhaps we should start a "Benchmark Results" forum like 3Dmark has, and have predefined criteria for the user to fill in.

Thank you for your time,

Frank Russo

That sounds like a good idea. Especially considering all the post from people asking if their results seem right.

Steve

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I upgraded to the 15K Cheetah from IDE Raid about 5 months ago. All I can say is there is no going back (well at least on my main computer). I keep an IDE in the computer for storage, mp3s, and Swap file. So I get the benefit of speed and space. When the Cheetahs come down in price I am going to hook another one up to my Raid Card, woohoo. If you are on a budget, IDE is still nothing to bark at.

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CPU usually is...

ATA CPU Utilization is a function of the Controller' date=' it's BIOS, it's driver rev, and the model of drive being used. Generally speaking, ATA CPU utilization is higher than SCSI.

In reality, a properly configured system should display little to no difference in CPU Utilization when compared to SCSI.

Frank Russo[/quote']

Agreed, but I as prob the majority of DIYers have Via ctlrs or Promise, (etc) sourced by Via chipsets. I expect it as a given for the low cost systems I tend to use at home.

My Apple using friends don't care so much about technical details as command queueing, transfer rates, etc just feel. In which SCSI feels faster despite synthetic benchmarks which IIRC suggest ATA & SCSI are comparable. I have no knowledge of technical info or benches on Apple's chipsets or ATA ctrl...

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Well if you have an Apple then you have more pressing problems to deal with, such as crappy system bandwidth ;)

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