Sata transfer rates vs RPM

weedn

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quick question

looking to buy a new HDD, my SSD and 200 GB HDD is not even close to enough storage for me, so im looking for either 1tb or 2tb

not too sure on the differences in performance, newegg has a deal right now for a 1tb caviar black 7200 rpm for $120, but its only sata 2 interface, however i could pick up a 2tb caviar green drive with sata 3 interface, but there only 5400 rpm for $130

im mainly going to be using the drive for storage, backup and games, since my OS is installed on my SSD

what would be the best bet here based on my needs
 
Solution
Media servers don't really stress the disk all that much, except maybe for caching. Any drive, probably even one from ten years ago, could handle the read rate for a media server. There's an easy way to estimate how much bandwidth you'd need to serve a file.

Let's say you have a 720p rip on your machine, at 4.5 GB. This movie is 90 minutes long, and you want to serve it from the media server. So, at minimum, your drive needs to be able to read 4.5 GB of data in the time it takes the movie to play. That's only about 0.85 MB/s.

Because the initial buffering is going to hit the disk harder, you'll have a higher utilization there, so let's say we need to load the first minute of data (about 50 MB) as quickly as possible, say in under 5...

willard

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Mechanical drives cannot come close to saturating a SATA II link, so they see no benefit from SATA III. I don't think it's very likely that mechanical drives will ever need to move to the SATA III standard. Their bandwidth is constrained by other factors.

A 7200 RPM drive, however, is going to be much faster than a 5400 RPM one. It will also have lower latencies. In general, green drives are a bad investment unless you really don't care about access times. If you're planning to put games on the drive, or anything else that's not big dumb media files, you absolutely want to pony up for the 7200 RPM drive.
 
Even though the Caviar black is "only" SATA 2 - it will never fill the bandwidth available on SATA 2 (300MB/s), most HDD's top out around 150-200MB/s (200MB burst rate) which even SATA 1 is capable of handling.

What exactly do you want? More storage space? or slightly faster speed? The caviar black will be faster than the green drive, but the green drive obviously has more space.
 

weedn

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thanks for the info

part of the storage factor is going to be media files, but im not a go big type of person and i dont have any gigantic blu-ray or HD media files, nor do i need them, its all just standard size stuff, got about 300GB worth on an external and i would like to be able to back it up to the new drive, also backup the system on the drive,

i could however, use the 200 GB drive for games, its only sata 1 i believe but its a 7200 RPM seagate barracuda, and if the sata connection doesnt really bottleneck the games in any real way i could use that instead and just use the new drive for media storage and system backup
 

weedn

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mostly for storage and a system backup

but i have WMP setup on my 2 xbox 360's in the house, and i also want to be able to stream video media off the drive onto the xbox's ,would the RPM affect this in any way?

i also see that the black drives seem to be more reliable then the greens and have longer warranty
 

frombehind

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rotary hard disks are slow by design - not intentionally, it just taskes more time to read information from a spinning disk platter with the drive head moving from sector to sector then it does from a chip that is always accessible.

as for the sata 2 vs sata 3 bus for a rotary disk... Think of yourself on a bicycle - pedalling for dear life. All you can manage is... say 20 miles per hour. Are you going to go faster then 20 on a road that has a speed limit of 45 miles per hour then on a very similar road where the speed limit is only 25? Dont think so :D
 

willard

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Media servers don't really stress the disk all that much, except maybe for caching. Any drive, probably even one from ten years ago, could handle the read rate for a media server. There's an easy way to estimate how much bandwidth you'd need to serve a file.

Let's say you have a 720p rip on your machine, at 4.5 GB. This movie is 90 minutes long, and you want to serve it from the media server. So, at minimum, your drive needs to be able to read 4.5 GB of data in the time it takes the movie to play. That's only about 0.85 MB/s.

Because the initial buffering is going to hit the disk harder, you'll have a higher utilization there, so let's say we need to load the first minute of data (about 50 MB) as quickly as possible, say in under 5 seconds. That gives us a peak speed requirement of about 10 MB/s.

Even the worst 5400 RPM drive should be able to handle 10 MB/s, and 0.85 MB/s is a pathetically light load.
 
Solution

weedn

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hmm, thats a pretty good analogy :D

i think ill go with the 1TB caviar black

it will likely be a long time before i fill that up anyways, and by then maybe these HDD prices will drop and i can get another, or a bigger one

i have a much better understanding of these matters now, thanks
 

frombehind

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Best of luck in your endeavors :D