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Data channels

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May 28, 2006 3:21:47 AM

Im planning a new build and wanted to see how I could improve performance from a hard drive point of view. Raptors seem pretty expensive for the small space you get and raid really has little benefit on gaming. The most interesting and cost effective solution I came across is having multiple hard drives on different data channels. Example
Hard drive #1 on Primary IDE Channel - Operating System
Hard drive #2 on Secondary IDE Channel - Applications
Hard drive #3 on Raid controller or PCI card - Swap File/Storage

The theory is that when 2 drives are sharing a same IDE cable and data channel the maximum bandwith of the drive is reduced if both drives are in use. This is an issue in windows XP because the OS is always running in the backround, a game is running and the swap file is ablazin between the two of them, the data channel gets a little choked at this point as well as the hard drives read head because its all over the place. Now this is proven to be effective but Im wondering if anyone has any knowledge of how it would work on SATA channels as I intend to use 3g/s sata drives. Does each sata connection have its own data channel just like IDE, or are they maybe paired? is it on a motherboard to motherboard basis? Any info would be appreciated. Tons of info was available for this subject on IDE but I couldnt find any on SATA. Thanks for any help.

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May 28, 2006 4:13:54 AM

SATA doesn't work in the same way PATA works. In SATA, each drive has its own channel unlike PATA where 2 drives share the 1 channel.
May 28, 2006 4:15:29 AM

Thanks for the reply, so if I get what your saying If the motherboard im looking at has say four 3g/s sata connections and I put a hard drive on each I would get the same effect?
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May 28, 2006 6:09:46 AM

Quote:
Thanks for the reply, so if I get what your saying If the motherboard im looking at has say four 3g/s sata connections and I put a hard drive on each I would get the same effect?



Affirmative.

Each SATA drive gets 150MB/sec or 300MB/sec interface bandwidth.

However no hard drive can even get close to that.

The fastest 7200RPM SATA drive gets about 73MB/sec.

The fastest 10000RPM SATA drive gets about 88MB/sec but is not worth it because of the cost.


Anyway you are much better off with several SATA drives and 0 ( zero ) PATA drives
May 28, 2006 7:41:18 AM

Quote:
Im planning a new build and wanted to see how I could improve performance from a hard drive point of view. Raptors seem pretty expensive for the small space you get and raid really has little benefit on gaming. The most interesting and cost effective solution I came across is having multiple hard drives on different data channels. Example
Hard drive #1 on Primary IDE Channel - Operating System
Hard drive #2 on Secondary IDE Channel - Applications
Hard drive #3 on Raid controller or PCI card - Swap File/Storage

The theory is that when 2 drives are sharing a same IDE cable and data channel the maximum bandwith of the drive is reduced if both drives are in use. This is an issue in windows XP because the OS is always running in the backround, a game is running and the swap file is ablazin between the two of them, the data channel gets a little choked at this point as well as the hard drives read head because its all over the place. Now this is proven to be effective but Im wondering if anyone has any knowledge of how it would work on SATA channels as I intend to use 3g/s sata drives. Does each sata connection have its own data channel just like IDE, or are they maybe paired? is it on a motherboard to motherboard basis? Any info would be appreciated. Tons of info was available for this subject on IDE but I couldnt find any on SATA. Thanks for any help.


I guess this can be a benefit and a hinderence. Having 2HDD's on one

cable, should only be a problem, if you're accessing both drives at once.

If you have an HD and a DVD-ROM on one channel(IDE) and you are,

say, installing a program...or worse...playing a game from the DVD, then

the HD and DVD are going to be competing for the available BW, which

would be more of a disadvantage. You have to decide which is more

advantageous to your usage patterns. GL :) 
May 28, 2006 2:09:36 PM

Quote:
Thanks for the reply, so if I get what your saying If the motherboard im looking at has say four 3g/s sata connections and I put a hard drive on each I would get the same effect?



Affirmative.

Each SATA drive gets 150MB/sec or 300MB/sec interface bandwidth.

However no hard drive can even get close to that.

The fastest 7200RPM SATA drive gets about 73MB/sec.

The fastest 10000RPM SATA drive gets about 88MB/sec but is not worth it because of the cost.


Anyway it you are much better off with several SATA drives and 0 ( zero ) PATA drives

Thanks for the reply linux, But it would also increase performance because the OS hard drive would only have to handle the OS stuff, the application drive would only have to handle the application stuff and the swap file drive would only handle the swap file (all that is in theory i know there will be small amounts of overhead) I was just hoping this setup would eliminate sort of the queing of waiting in line to use the hard drive head because afterall the slowest part of the hard drive is the read/write head correct?
Well thanks again for all the help.
May 28, 2006 2:30:07 PM

While all that works in theory, I think in practice the benefit is marginal at best. If you want to just experiment with it that's one thing, but hoping to gain any huge performance increase I personally think isn't worth all the effort and extra cost.

I've also had issues with running the swap file on a different partition/disk, and then that disk developes a problem and suddenly you are unable to boot the OS, even though that partition/disk is perfectly fine. Sometimes it allows you to get in and recreate the swap file, sometimes it just puts you in an infinite reboot/login loop and you end up having to reinstall the OS.

Over many years I've experimented with different set ups, just like you are suggesting. Raid arrays, swap files on different disks, etc. In the end, I don't mess with it any more because the gains were barely noticable in day to day use and it wasn't worth the trouble.
May 28, 2006 3:04:19 PM

SCSI, RAID, RAM disks, faster SATA drives and Linux / BSD will improve performance.
May 29, 2006 3:18:11 AM

Quote:
is linux, in your opinion the answer to all of lifes problems or just computer ones :) 



That's because Linux / *BSD and Unix can be used to accomplish almost anything.

Whatever they cannot do out of the box they can be modified to do because they are almost infinitely customizable. :-D
May 31, 2006 8:34:54 AM

There is zero real world benifit from seperating your OS & Applications & Swap file with Windows XP.

How often is your OS going to be loading part of itself off the hard drive, while an application is being loaded, or vitual memory is being used. Roughly 0% of the time. Whatever it is, its small enough that its not going to show up on any benchmark.

Keep your programs and your data on seperate partitions. Use 2nd drives for hardcore video editing or more commonly to store backups.

Ocassionally move some backups to DVD+RW just in case.
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