Guest Eugene

Western Digital Caviar RE2 WD4000YR

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I wish that they would be even more aggressive and do things like have each platter have an independent head (so that you would have intra-drive striping); I am amazed that no manufacturer currently does this.

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Per the SR FAQ here, it's not a trivial matter to do so. Just thinking about all the design issues is making me cringe.

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Reading that FAQ was interesting, and did not make me cringe at all. Of course, I say this as someone who has never worked for a disk drive manufacturer either!

I am sure that the economics (the manufacturers want to force you to buy more drives, plus they are a low margin commodity industry with little luxury for technological innovation) are what are are supressing the vastly superior performance that you could get from internal RAID (e.g. n times data throughput where n is the number of platters).

Still, as the FAQ itself notes, all of the technical issues can be addressed by straightforward use of current technology:

Factor #1 (Head offset on a single actuator) is solvable simply by using dedicated actuators for each platter. (The probably more optimal solution of having multi-stage actuators is what would require substantial technology development; this could wait for the future).

Factors #2 (Read channel bandwidth limitations) and #3 (Servo complexity) are likewise simply solved by having dedicated read channels and servo systems for each platter. (Again, the probably more optimal solution of having a single but more sophisticated channel chip and servo system is what would require substantial technology development; this too could wait for the future).

Factor #4 (Interface bandwidth limitations) is a marginal issue with SATA 150 and is not an issue at all with SATA 300 which is now already a production technology. Even if SATA 150 is used, heck, I would be GLAD to have a drive which is saturating that interface compared to what we currently have!

Note also that unlike SCSI, SATA is a point-point (not shared bus) architecture so that if you made a RAID of drives each of which is also an internal drive, then it should scale linearly. (At this point, you would need to worry about the data throughput of the RAID controller.)

So, you can achieve internal RAID right now with very little new technology having to be developed. Yes, the solution of parallel everything (actuators, read channels, servos) is sub-optimal compared to what developing new custom technology might do, but it should still work perfectly fine as far as performance is concerned.

Then the remaining question to my mind is what IS the actual cost of a hard drive's components? How much does each actuator cost? Each read channel chip? Each servo system?

For the sake of argument, lets suppose that each of those 3 system costs $10. So, in a conventional drive, they total $30.

Lets consider a prime candidate for an application of this technogy, the 74 GB Raptor which has 2 platters. Adding dedicated components to each drive just increased the component cost by an extra $30. Lets suppose the price increase that needs to be passed onto the consumer is double that, $60. Would you be willing to pay $60 extra for a Raptor with twice the data throughput (~140 MB/s)? I would!

Or consider the 4 platter WD4000KD: if each platter had dedicated components and the total component cost is an extra (4 - 1) * $30 = $90 so the extra cost to the consumer is 2 * $90 = $180. Again, I would personally pay $180 extra (~$410 total if the YR's $228 price at Newegg is used, http://www.newegg.com/Product/Product.asp?...82E16822144424) in order to get a drive that would offer me ~4 * 70 = 280 MB/s data throughput.

Clearly, my argument above made lots of assumptions about component costs and what they lead to as final customer price increases, as well as on price/performance tradeoffs for customers. If you have better data, please post it. Also, if anyone who actually works for a drive manufacturer is reading, I would love your perspective.

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"The WD4000 compares favorably to other WD drives, but remains behind its current competitor from Seagate (7200.8) when it comes to low level performance

If low-level tests are all that matter, why do sites struggle to devise meaningful high-level tests?

I understand that low level results may be deceiving and that true high level results are to be preferred; that is an excellent analogy with procesor clock speeds, by the way.

I should have cited this page from tomshardware review which focuses on what they call "Application" benchmarks (which I assume correspond with your high level tests). Notice how the WD4000KD is strictly in the middle of the pack in their first test (XP startup) and several notches down on the second (FileWrite). Actually, now that I am looking more closely at this, they seem to not have done that thorough of a job doing high level tests, so maybe their results are not too meaninful.

Since some readers frowned on the practice, our "elsewhere" section (that is, our commentary pointing out why one should be wary of various other tests) has gone away, but many sites still need it :P

Please put it back!

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Guest Eugene
How did you turn off NCQ on the drive? Was it a specific utility you have?

With our controller, the SI3124-2 reference board, NCQ is toggled via a registry setting.

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Clearly, my argument above made lots of assumptions about component costs and what they lead to as final customer price increases, as well as on price/performance tradeoffs for customers.  If you have better data, please post it.  Also, if anyone who actually works for a drive manufacturer is reading, I would love your perspective.

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The reason all the design concerns make me cringe is because I wrote most of that FAQ article. :lol:

Component costs are trade secrets and not something anyone who really knows can divulge to a public forum like this. I can say that the industry is researching dual-stage actuators, but I have yet to hear of any work on multiple actuators in a drive. My guess is the form factor concern is the overwhelming strike against it.

Assuming each head was given its own electronics, that's a bunch more stuff to fit on a typical PCBA. Most boards (at least in the ATA world) are now half-sized or smaller. They don't extend across the entire underside of a drive. There isn't likely enough room to fit all those electronics, so that'd require a larger board. In turn, that significantly impacts price, since the biggest factor in component cost is probably volume.

The other cost you ignored is development cost of testing and coding for a more complicated system. Mechanical parts are fairly easy to estimate pricing for, since it's pretty much your material cost, any machining/fabrication costs, and maybe some overhead. But code? Maybe you can guess it'll take X programmers Y time to write new firmware, but it can widely vary depending on so many factors. And code has to cover not just that used to run the drive, but also any code used in the manufacturing process (test code and the like).

My suspicion is the development cost involved will not get recouped considering the relatively small market out there.

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Here's the answer from WD re using the YR in a non-RAID config on a RAID enabled controller:

Thank you for contacting Western Digital Customer Service and Support.

I would not suggest using a RAID edition drive in a non Raid environment. I would suggest using the WD4000KD. Please see the specifications below.

Title: Specifications for the 400GB Caviar SE16 Serial ATA hard drive (model WD4000KD)

URL: http://wdc.custhelp.com/cgi-bin/wdc.cfg/ph...ated=1127843454

Sincerely,

Dallas L

Western Digital Service and Support

http://support.wdc.com

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Addendum to previous post: So, the answer is short on details and leaves one wondering. I have read elsewhere that TLER induced errors are only an issue in a high I/O scenario and that the average desktop would not suffer any ill effects. However, being a coward at heart, I opted to order the KD from ZipZoomFly for $220, free 2day shipping.

I also ordered the 160G (single platter) version of the Seagate 7000.9 from NewEgg. Should make an interesting pair.

Edited by ho

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So is it safe to use the RE2 in a mirroring scenario under Nforce4? I want to buy a pair of 400GB RE2 and config them in raid1 for a little workstation up 24h/24 in medium I/O...

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So is it safe to use the RE2 in a mirroring scenario under Nforce4? I want to buy a pair of 400GB RE2 and config them in raid1 for a little workstation up 24h/24 in medium I/O...

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It would depend on the level of error correction offered by the nForce chip in a RAID environment. I don't know how easily one could find an answer to that. It would be very helpful if WD would publish a list of RAID controllers compatible with their drives.

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I've had three RE2s for a month on a desktop/workstation computer (nForce4) without problems.

If I undestood the TLER system correctly it might cause trouble on non-raid system only under high I/O load and when big errors occur. My disks have been under heavy load (even as a busy fileserver temporarily) an there has been no trouble at all.

Edited by Viper8

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I've had three RE2s for a month on a desktop/workstation computer (nForce4) without problems.

If I undestood the TLER system correctly it might cause trouble on non-raid system only under high I/O load and when big errors occur. My disks have been under heavy load (even as a busy fileserver temporarily) an there has been no trouble at all.

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Hey Viper,

I'm putting a single one into a new AMD system (Raptor's [2] RAID0 as C:] and all data and backups to a partition on this Big RE2 - you mention 3 drives. Did you RAID them?

Sounds like 'not', but wondered. I'll have it built in about two weeks. Will make sure I drop back any findings. Anyone ELSE running this drive alone????

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Guest Eugene

Cross-posting this from another thread:

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1) By "raid controller," the firm is specifically referring to controllers that suppport functionality to SCSI's tear- i.e., the controller of course has to have logic that understands the drive is giving up on error recovery after eight seconds. The rule of thumb is that a "raid controller" in this case must be "hardware"... it should support hardware raid 5, for example. This rules out the ICH5, ICH6, and garden-variety controllers such as the SATA Fasttraks.

2) TLER is -not- automatically diasbled in non-RAID situations. Rather, the setting can be toggled via facilities in the drive's SMART settings. They weren't able to tell me right then and there where the setting is, but promised to get back to me on it. That said...

3) The Caviar SE16 WD4000KS is quite similar to the WD4000YR, and is the drive that WD recommends for consumers not looking to incorporate the unit into a multi-user array. Three differences- A) the WD4000YR enjoys an extended 24-hour factory burn-in period as opposed to the WD4000KS's lower 8-hour window. This significantly reduces the drive's infant mortality rate. B) TLER is disabled. C) WD backs the drive with a three- rather than five-year warranty. Those are the only differences.

The dichotomy in WD's SE16 line is rather intriguing. The 400 GB version basically descends from the Raptor's mechanics and electronics while the 250 GB unit is a member of the firm's more traditional Caviar line.

------------------------------

Given the similarity between the two drives, there really is little reason to go with the RE2 unless you have a hardware RAID controller (supertrak, megaraid, 3ware) in place.

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Cross-posting this from another thread:

[CUT]

The dichotomy in WD's SE16 line is rather intriguing. The 400 GB version basically descends from the Raptor's mechanics and electronics while the 250 GB unit is a member of the firm's more traditional Caviar line.

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Given the similarity between the two drives, there really is little reason to go with the RE2 unless you have a hardware RAID controller (supertrak, megaraid, 3ware) in place.

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Your informations are very useful, but at this point i/we need an intensive testing of the Caviar RE2 under "desktop conditions"; i like the idea of two RE2 in mirroring under nforce4, because i need a machine up 24h/24 with HDs tested for full duty cycle. To be or not to be... :rolleyes:

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---------------------------------

2) TLER is -not- automatically diasbled in non-RAID situations. Rather, the setting can be toggled via facilities in the drive's SMART settings. They weren't able to tell me right then and there where the setting is, but promised to get back to me on it. That said...

------------------------------

Given the similarity between the two drives, there really is little reason to go with the RE2 unless you have a hardware RAID controller (supertrak, megaraid, 3ware) in place.

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No reason at all unless one cares about a 5 year warranty. Regarding point 2 above, are you saying that TLER for this drive can in fact be disabled?

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---------------------------------

2) TLER is -not- automatically diasbled in non-RAID situations. Rather, the setting can be toggled via facilities in the drive's SMART settings. They weren't able to tell me right then and there where the setting is, but promised to get back to me on it. That said...

------------------------------

Given the similarity between the two drives, there really is little reason to go with the RE2 unless you have a hardware RAID controller (supertrak, megaraid, 3ware) in place.

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No reason at all unless one cares about a 5 year warranty. Regarding point 2 above, are you saying that TLER for this drive can in fact be disabled?

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I would like to know too, if TLER can be disabled. I have a mobo that uses the ICH7R, but I do not know if it supports TLER.

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I appreciate all the work that went into this review, but I am curious why it only compared to desktop drives.

To properly evaluate this drive I suggest the appropriate comparison choices would be the Seagate NL35, the earlier WD 250SD, and perhaps the Hitachi Deskstar 7K500 500GB (0A31619).

??

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Guest Eugene
I appreciate all the work that went into this review, but I am curious why it only compared to desktop drives.

To properly evaluate this drive I suggest the appropriate comparison choices would be the Seagate NL35, the earlier WD 250SD, and perhaps the Hitachi Deskstar 7K500 500GB (0A31619).

??

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The 2500KS (which we have previously reviewed) may have warranted inclusion into the review, yes. As for the rest, you're looking at a review that takes place with a historical snapshot. At the time the WD4000YR review was completed, we had not completed testing on (or even necessarily received) samples of the NL35 and the 7K500. So, the chosen drives were the next up. You can see that the NL35, upon which testing was completed later and whose review was published later, incorporates the 4000YR in its comparison graphs. Likewise, the 7K500 review, the newest of the bunch, is compared against both the NL35 or the 4000YR.

What you're implying is either:

1) The WD4000YR should not have had a published review but rather have been witheld until tests on other similar drives would have been complete. This mean that despite having readily available results for this drive, we would sit back and delay several weeks until a roundup is published.

or

2) We should go back and retroactively change the graphs in a review published on a given date. Which would then mean that the commentary associated with the review would then need to be reworked... which then means we're basically writing another review on the same product.

Both options are not ideal in my opinion. Rather, I hope that readers keep review publish dates in mind when seeing what drives are being compared to what competition and also keep in mind that StorageReview stands alone in offering readers a tool that allows them to choose comparisons of any drives they wish.

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In reguard to the very recent news item about the differences between the WD4000YR and the WD4000KD, I have only piece of information keeping me from buying the KD over the YR.

Can TLER be enabled in the WD4000KD? If so, the infant mortality scenario won't matter all that much, not at all if it survives the first 24 hours. If TLER can be enabled and it survives the first day of operation, then what I understand is that you will basically have a WD4000YR with a 3-year warrenty instead of a 5-year warrenty, and you may end up paying a little less.

I have a price range I'm waiting for these to reach, and the WD4000KD will probably get there first.

Thanks.

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i've noticed on recent tests, that there's no noise measurements for "seek" for the HDs?

is the seek/write noise of the Raptor significantly higher than this drive?

I'm trying to decide which of the two to buy for my boot drive :)

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Ok, ladies and gents!

I bit the bullet back then and just bought the drive.. I received it today, I havent put it in yet but I've been reading tons and tons about the drive wanting to live in a raid setup and not a single user setup.

I havent got a raid setup and neither am i thinking of getting a raid card and another one of these drives.

I do have the DFI board with the Nforce raid controller but from my understanding this is not sufficient...

Even if i got another drive and mirrored them, the raid controller on the nforce 4 is just some 'wanabee' controller so 133t boys can run there raptors in raid 0 and think there games run 2000 times faster..

the question i am now puzzled with is, return the drive and get the alternative.. or take the risk and use it in the computer as a single drive... do we have results? reports? any problems that have happened? any kind of history from other users? opinions?

thanks folks..

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Install it as a "secondary drive" and test it for a week or two with various tasks, for example games, defrag, scandisk, creation of multiple big archives all togheter to stress the disk eavily... If it work, it's ok to use it as a single drive, in my (VERY) humble opinion :P

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Regarding the WD4000KD vs WD4000YR comparison, you include the following statement regarding NCQ support:

Though spec sheets fail to mention it, the 400 GB SE16 supports NCQ. It’s the same physical drive as the RE2, a drive targeting the multi-user market where such a feature is a necessity.

Yet all other references to NCQ support I've seen online state the opposite. For example:

NCQ MIA?

Noticeably missing from the Western Digital Caviar SE16 WD4000KD HDD's specifications is support for Native Command Queuing (NCQ). The benefits of NCQ have been discussed previously, but in essence NCQ allows the hard drive to retrieve data more efficiently off the disk. If you would like to read about the benefits of NCQ, check out the Gigabyte GA-K8NXP-9 motherboard review where we go into depth on the technique.

The official reason from Western Digital about the lack of NCQ support (even though most manufacturers have jumped on board already) is because none of Intel's Southbridge chipsets support this feature. Considering Intel systems make up the majority of the market, and NCQ offers no real world performance gain, I suppose including NCQ support is not totally necessary.

Source: http://www.pcstats.com/ArtVNL.cfm?articleid=1885&page=2

The WD4000KD hard disk holds very similar specifications as the Hitachi and Seagate 400GB models. The WD drive holds 16MB cache, 7200 RPM, Serial ATA (150MB/s), four 100GB platters, 8.9ms read seek time. This drive does not come with Native Command Queuing, however this is not necessarily a bad thing. While NCQ is a welcomed technology it hasn't yet showed significant improvements in performance with it enabled.

Source: http://www.techwarelabs.com/reviews/storag...D/index_2.shtml

With both of those reviews linked at WDC's website (http://www.wdc.com/en/products/products.asp?DriveID=159&Language=en), it sure would seem in WD's best interest to correct this error or at least detail the NCQ support on its own site! Are you completely sure that NCQ support is present?

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Guest Eugene
With both of those reviews linked at WDC's website (http://www.wdc.com/en/products/products.asp?DriveID=159&Language=en), it sure would seem in WD's best interest to correct this error or at least detail the NCQ support on its own site! Are you completely sure that NCQ support is present?

WD does not believe its in their best interest to play up lack of differences between the two drives. As a result, they've "created" differentiators such as not listing NCQ on the SE16 and citing only 600,000 hours MTBF vs the RE2's 1.2 million.

You ask me if I'm "completely sure" that NCQ support is present... take a close look at the IOMeter scores turned in by the WD4000KD in our database with NCQ enabled and disabled :P

Honestly, I posit this as testament to the fact that here at SR we don't take the manufacturer's word for it and simply parrot a spec sheet.

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Honestly, I posit this as testament to the fact that here at SR we don't take the manufacturer's word for it and simply parrot a spec sheet.

One reason I've enjoyed reading your reviews/articles over the years. Thanks for the response.

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