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2 x wd10eacs in raid0 vs 2 x wd1500adfd in raid0

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December 27, 2007 4:04:36 AM

I'm helping a friend build a machine which will be used mostly for shrinking dvd's for backup and then burn them with four dvd burners. Since all he need is performance. I recommended him to use two Raptors (wd1500adfd) in raid0. Now while he was waiting for the two ordered raptors to arrive, we tried the machine with two WD 1Tera (wd10eacs) just for the fun of it and he tried the dvdshrink software with them. Now after the two raptors have arrived, he claims that the process went much faster with the two 1TB WD(wd10eacs) in raid. (NOTICE: He uses the program dvdshrink to compress the dvds and then burn the compressed files with four dvd burners simultaneously)

Here are the specs:

CPU: Core2Quad Q6600 2.40GHz
MB: ASUS P5K-E
RAM: 4Gb Pqi DDR2 800MHz
VGA: ASUS 7300GT Silent
PSU: Cooler Master 1000Watt Real Power
ODD: 4 x Pioneer DVR-212
HDD:
FIRST TRIED: 2 x Western Digital 1 TeraByte Green power WD10EACS in RAID0
SECOND TRIED: 2 x Western Digital Raptor 150Gb WD1500ADFD in RAID0
..and lots of coolers..

Now the only difference before we replaced the two 1Tb WD with two Raptors was that the Ram was 2Gb.
The operating system used was Windows XP Pro 32bit.

Could this performance drop be because of the issue with Windows XP not using the whole RAM(It shows only 3.5Gb when 4Gb are present).

Also the first time we tried with the two WD terras was a plain windows installation with drivers only and the needed software. And the second time there was some more software installed with only AV in working in background.

Could the reason be in the things changed or are two WD terras simply better than two WD Raptors in RAID0 ?


Western Digital Raptor 150Gb 16Mb cache 10000Rpm 1.5Gbps
model: WD1500ADFD
http://www.wdc.com/en/products/Products.asp?DriveID=189


Western Digital WD10EACS 1Tb 16Mb cache 7200Rpm 3Gbps
model: WD10EACS
http://www.wdc.com/en/products/Products.asp?DriveID=336


EDIT: Oh and I may seem new to you, but I'm a long time reader at these forums :) 
December 27, 2007 9:56:15 AM

"claims that the process went much faster".

He's wrong it was slower! How can he make a claim like that without substantiation?

memory should not make a big difference, software could, drivers could, cutting a different movie could, too many unknowns to give an accurate answer.

December 28, 2007 8:15:29 PM

I've just did a test with two systems the same like the one I've mentioned in my original post with the HDDs only difference. One with the both Western Digital 1TB WD10EACS in raid0 and another with the two raptors WD1500ADFD in raid0. The OS tested was Windows 64bit. My friend showed me how he got those results and it turned out to be true.

First he is copying the content from four DVDs into one folder with a program called DVDShrink and then he encodes the dvd format videos one by one each into separate folder. The encoding time with the tera caviars WD10EACS was about 40s average and the raptors WD1500ADFD about 1:10s ??? The rate at which the process went was like this:

HDD: Rate: Overall time: Size:

WD10EACS 53 MB/s avg. 41s avg. 2.2GB

WD1500ADFD 35 MB/s avg. 1:10s avg. 2.2GB

I'm so disappointed by the raptors performance as I was considering it to be the best of the best. Application loading may be a bit faster, but read and write speed is just bad..

Can someone please confirm this, am I doing something wrong here? They are very noisy while doing that operation, is it possible that some of it may be faulty or something? They are brand new, they shouldn't be but..
Related resources
December 28, 2007 10:30:04 PM

OK, first of all, I don't know how you're configuring DVDShrink, but if the operations you're talking about are taking 41 seconds vs. 1 minute and 10 seconds, you're not doing any encoding. You're simply copying data. Transcoding a DVD with DVDShrink takes at least several minutes for a 2 hour movie, and that's with the fastest Core2 Duos available. Doing full reencoding with something like CinemaCraft Encoder and DVD Rebuilder takes even longer.

If you were actually encoding/transcoding, the hard drives wouldn't matter at all, since the bottleneck in such operations is not the hard drives, but the processor's speed and power.

Second, when doing DVD operations that involve copying a lot of data back and forth (i.e. multiplexing .m2v & .ac3 streams into .vob files during authoring, or making an .iso file out of a set of .vobs & .ifos), you will have much better throughput and performance by placing the source data on one hard drive and putting the destination file or folder on another hard drive. What you're doing in your setup is copying data from one folder to another folder on the same volume of the RAID 0, which is doing massive seeks back and forth to read some data, then write some data. By splitting the task with a single drive doing all the reading and a second drive doing all the writing, the overhead for seeking goes to nothing, and you can realize data transfer rates near the published benchmarks for STR.

The reason the Raptors are not performing as well as the 1TB drives here is because of the seek distances. The Raptors have small data capacity. To go from the beginning of the source files to the beginning of the target files when going back & forth for reading/writing, the Raptors seek a lot farther (more tracks) than the 1TB drives do. So even though the Raptors head movement is faster, it's also farther, and it loses time compared to the 1TB drives. Of course, if you configure the system like I stated, they won't be seeking back & forth at all.

Third, because copying data like this is a task that depends on STR and not access time (when configured for split drive operation like I said), and because the amount of data you're dealing with is in the GB range (DVDs), the WD 1TB drives are a far better fit for this application than the Raptors are.

I have a machine set up for reencoding DVDs, and I have it configured as follows:

- WD Raptor 74ADFD for C: drive (Windows & applications).
- Seagate 500GB for D: drive
- Another Seagate 500GB for E: drive

My process goes like this:

- Rip my legally purchased and owned DVD to D:
- Re-author with DVD Remake Pro, output to E:
- Re-encode with CinemaCraft Encoder Basic and DVD Rebuilder to E:, using D: for intermediate files
- Burn my backup/working disc from E: to DVD
- Carefully store original out of reach of the kids :) 

By going back and forth between drives like this, I get maximum throughput on the operations that involve just copying data (the DVD Remake Pro output operation, and the DVD Rebuilder rebuild operation). No RAID is involved.
January 16, 2008 4:14:45 PM

First of all, sorry for this late answer, I went on vacation the day after I posted and then completely forgot about it.

SomeJoe, thank you for your informative post, your detailed explanation sounds very logical and I we were able to return the two raptors to the place where I bought them, and they were well not kind, but enough to accept them after I explained your interpretation :) 

I was assuming that its not encoding what I was doing because it went so fast, but since I've never worked with encoding dvd's myself and the process was going through the dvdshring software, I didn't know how to explain it. I guess dvdshrink is just copying the movies from one folder to a separate folder each, as you said.

So all in all I concluded that raptors, although with faster access time, are not meant for transfering big files. I did something similar as your configuration, except that I installed one raptor for os and only one 1Tb for dvdshrinking simply because I do not do much editing as you are, but more burning :) 

Thank you again for your throughful answer, it really helped me realize some things.
November 3, 2008 2:07:55 AM

spiritfly said:
I recommended him to use two Raptors (wd1500adfd) in raid0. Now while he was waiting for the two ordered raptors to arrive, we tried the machine with two WD 1Tera (wd10eacs) just for the fun of it...

...So all in all I concluded that raptors, although with faster access time, are not meant for transfering big files.


Necropsy, I know, but in case anyone else stumbles on this misleading thread, this is why:

wd1500adfd ... SATA 1.5 Gb/s
wd10eacs ....... SATA 3.0 Gb/s

... so your super fast Raptors (10K RPM) were doing pretty good considering you had them throttled with a SATA channel only 50% as fast as the Caviar Green drives (5400-7200 RPM) had...

No mystery here!
!