Raptor Vs Raid article

[smyke89 0]

this is an article i wrote last month (i have to write 1 article and make a lot of reviews each month...)

 

Once with stocking capabilities of hard disks and their performances, we can choose between speed and capacity, but we can also combine them.

 

Technologies have developed in all domains, being seen as a real blast, performance differences rising from year to year. But most components have evolved exponentially if compared to the models available on the market 10 years ago. This way, processors worked once at only 33MHz and now are reaching the 4GHz mark, memories have passed trough multiple generations, form SD-RAM to DDR, to DD2, and recently, DDR3.

 

Short history

 

Hard disks have not been forgotten by time, starting from ATA33 to ATA133, then evolution led to interface changing, in the 2 revisions on the market : S-ATA I (or S-ATA 150) and S-ATA II (or S-ATA 300). Besides, technologies once available only for high end models are now available for desktop users. Thus, Western Digital has introduced a series of hard disks that work at a 10.000rpm, compared to 7200rpm on regular models. This angle of approach is “borrowed” from SCSI hard disks, used on servers, with disks that spin at 10.000 and 15.000 rotations per minute. But transfer speed increase is not the only thing that has been modified with time. Now you can stock more information on the same space unit, with **** density raising and innovating technologies like Perpendicular Magnetic Recording.

The latter allows a quantity 10 times bigger of information to be stocked compared to longitudinal. As an user, i feel the need to have a computer that responds fast to my commands. Of course, all components of a PC are essential, so they create a whole, that rises up to my expectations, but i have considered 2 concepts referring to hard disks : speed and capacity. There is a myth out there that says if you want speed, you should choose a Western Digital Raptor hard disk, these being considered as ones of the fastest hard disks on the market for desktop users. This detail comes with speed loss, the Raptor being available in 3 models : 36GB, 74GB, and, lately 150GB. I have tested the 74 GB model. On the other side, if you want capacity, you should choose a 400GB hard disk. But, as innovations don’t give you the possibility to buy a hard disk with a large capacity at a low price, and Raptor hard disks not being that cheep at all, we raised a question : which is better : one Western Digital Raptor or 2 S-ATA connected in a RAID 0 matrix for a speed bonus.

 

 

end of part 1... (tomorrow part 2... it's a lot to write)

[smyke89 0]

The contestants

 

The WD Raptor model is part of a series of high-end products made by Western Digital. even tough it was launched on the market to be a product for small servers, it was adopted and well appreciated by home users because it was the only hard disk that could reach transfer speed encountered only at SCSI hard disks, that where very expensive. Once with the introduction of S-ATA technology, these could be connected to the modern motherboards without the use of an additional controller. The introduction of a Molex power controller made it easier to use their connectivity of this type of hard disk with older power sources that did not have an S-ATA connecter. even tough the series was launched in 2003, there is no other product that can attack this market segment , both models being considered “absolutely necessary” for gaming computers. Western Digital has recognized the big success they had with this products and has decited to continue the legacy with the Raptor X series, that benefits from a plexiglass pannel trough which you can see the disks and the reader heads during the use of the hard disk.

For the model i have tested (the 74GB), the producer specifies it’s resistance for a 1.2 million hours of functioning before possible errors may appear. The term they use is MTBF(Mean Time Betweed Failures). If we make a little calculations, it means about 50.000 days, or more than 136 years. Either if it is introduced as a marketing concept, like the life time guarantee some producers offer for RAM memories, to boost the user’s confidence in these products or to draw attention on a very performing line of products, this thing adds a confidence plus, a worth worthy step. The weight of this hard disk is about 882 grams and it uses up to 10.02W during the writing/reading cycles, and while idle, the Raptor uses 9.19W.

In the opposite corner, weighting 635 grams, with a 400 GB capacity, we have the Seagate Barracuda. This is produced by another big name in the field, Seagate, the oldest (and biggest) independent hard disk producer on the market. The hard disk line the 2 models we tested are part of is called Barracuda, and is on the market since 1992, followed by Cheetah, the first hard **** line with 10.000rpm and, in 2000 by the “X15”, that reached 15.000rpm. The models benefit from the advantages of the NCQ technology (Native Command Queuing), this allowing hard disks to receive multiple I/O (input/output) requests and then choose the requests to process. This way, knowing the own hardware details, the hard disk can find the best road on the disks, to avoid the overburden of the reading head.

 

end of part 2

[smyke89 0]

The testing procedure.

 

The hard disk testing was made using HDTach 3.0, SiSoftware Sandra 2007, PCMark 05 and HDSpeed. he have broken the test in 2 stages for each competitor : first we ran the tests for reading andr writing speed, then we divided the hard sisks in 2 partitions. At the Western Digital we made a 10GB partition, the second using the rest of unallocated space, proceeding the same for the RAID-connected hard disks, 10 GB for the first and the rest for the second. On these partitions we tested the time it takes to transfer a set of files from one partition to the other. Thus, we had a 4.48GB .iso image, and a kit of programs composed from 11.178 files, in 888 folders, with a total capacity of 756MB.

The Seagate Barracuda have been connected in a RAID 0 matrix, Stripping with a 64k cluster for a maximum performance.

 

PERFORMANCES

 

The results where broken down in two : 1.transfer speed tests and access time 2.information transfer between partitions. Using HDTach 3.0, Seagate disk obtained an average of 95MB/s and a burst speed of 213MB/s, while the Western Digital Raptor obtained an average of 71.8 and a burst speed of 138.4. We can see the Seagate Barracuda have won, the combined speed of the two hard disks combined in a RAID matrix being superior, while the Western Digital Raptor has handled better the information transfer from one partition to the other. A single thing about this test remains : the two Seagate Barracuda’s have heated up more than the Western Digital Raptor, a thing that matters in a configuration because temperature is essential for the system to work well. It is recommended that you use a cooling solution to maintain a low temperature, thus making the hard disks to last longer.

 

Conclusion

 

The price for a Raptor is about 200$, while the price for the 2 Seageates is about 600. If you whould use a Seagate Barracuda of 200G you whould have to pay only about 300-350, and you will the same speed. I think the difference is big betwen the capacity of the Raptor compared to the capacity of the Barracudas. I think the Seagate Barracuda is better option, even tough you pay more, you have approximately the same speed but a lot more space on your drive.

[wutske 0]

Good article, but I miss the part about RAID. RAID is a nice thing, we all know that, but it can be a b**** too. Stripping hdds creates an incredible performance boost, almost 200%, but the change to get a disk failure is 200% (lets say, 1 disk out of 100 fails, the means 1% chance, if you have 2 of them, there's 2% chance it'll fail. If you have 100 disks, you'll be 100% certain one would fail).

Edited December 30, 2006 by wutske (see edit history)