SATA 2.0 and 3.0

Hakane

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Hi,

I'm considering to setup an RAID 0 config. for my build. Currently I have one WD Caviar Green 500 GB (SATA 2.0 interface) and for the other drive I was considering WD Caviar Black 500 GB (SATA 3.0 interface). My motherboard only supports SATA 2.0 but the reason im chosing the 2nd drive as a 3.0 is for furture upgrades. Can the motherboard and HD work even though the board doesn't support SATA 3.0?

Thanks for helping me :)
 
To the question that you asked: Yes. If you connect an SATA II port to an SATA III device, or vice-versa, you will have an SATA II connection. It's guaranteed in the spec. Plus, keep in mind that you are using rotating-platter devices. These can't make use of the higher speed of SATA III connections; they only have SATA III controllers because it's cheaper to waste the speed than to produce controllers of both types.

However: Your RAID will suck, err, disappoint you with its performance. The Caviar Green drives are slow. They are intended to be slow, because the line is designed to save power. So harnessing a race horse and a plow horse to the same hitch will give you plow-horse speeds.

OBLIGATORY WARNING: RAID0 is highly subject to unrecoverable data loss. (It's not truly RAID at all, since the "R" stands for Redundant and there is no Redundancy in RAID0). Back up your data frequently. Even higher RAID levels should not be considered as a replacement for backups.

Also, you will get better performance from buying a 1 TB Caviar Black than you would from this array, so just spring for the 1 TB drive if you can afford it.
 

Hakane

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Thanks for the answer.

I know that Caviar Green are slower than Black, but why will the black version be slow when combining those two in a RAID0?

And why would a 1TB drive be faster? (i guess the 1TB have 64 MB buffer size that why?)
 
The 1 TB drive would be faster because you would have all 1 TB of your storage on the new Caviar Black instead of half of it on the Green. That is, a 1 TB Black will be faster than the 1 TB RAID0 comprised of a 500 GB Black and a 500 GB Green. Plus, you'd have the Green drive around to do backups to.

RAID0 writes alternate blocks, one to one drive, one to the other. So the Green drive in the pair will throttle the pair significantly.
 

dalmvern

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Typically its not recommended to mix drive types and speeds. To optimize your performance its best to have identical drives in the RAID. That being said, if you do mix drives, the speed of the RAID will be limited to the speed of the slowest drive.
 
Primary reason that Raid0 does NOT help a boot/program drive:
Raid0 only really speeds up sequencial reads/writes, Does nothing to improve access time and very little improvement in small file random read/writes - where ALL the action is. For a Boot/program drive you will find that 2/3 s of your files will be on one drive or the other (using default 128K strip)- NOT split. In fact Half of your files will be 16K or less.

Where raid0 does shine is as a data disk for LARGE files such as dvd Video files (typically 1 gig), Blu-ray files (can be upto 40 Gigs), Large spreadsheets, cad/cam drawing files, and large jpeg photos. And in this case you take a performace hit using a low speed HDD for the reason WyomingKnott stated as compared to say 2 WD black.
 

Hakane

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aha, WyomingKnott I misunderstood you, I thought you ment 2x 1TB :)

Thanks folks for the very usefull answers :)