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Desktop HDDs: Differences

Tom’s Winter 2008 Hard Drive Guide
By

Hard drives are storage devices based on rotating magnetic media and differ in various respects—the important being the recording technology used. These days, all manufacturers utilize perpendicular magnetic recording technologies (PMR), which means that the alignment of magnetic domains is now vertical. Hard drive makers switched from longitudinal to perpendicular recording to avoid magnetized elements influencing each other, a phenomenon known as superparamagnetism. This allowed recording densities to be increased considerably, a trend that will continue. Hitachi forecasts that in the coming years, the traditional 3.5” form factor will store up to approximately 50 TB using patterned media and heat-assisted recording.

Platter Count

Other important hard drive parameters include the spindle rotation speed, interface, cache size, and the number of platters used. All high-capacity 3.5” desktop hard drives are based on several platters and enterprise units often have several as well; 2.5” notebook hard drives usually only use one or two platters due to space constraints and the need for robustness. Most terabyte drives are based on three platters today, including the Hitachi Deskstar 7K1000.B, Samsung Spinpoint F, Seagate Barracuda 7200.11, and WD Caviar series—while the first generations of terabyte hard drives required up to five platters (such as the Hitachi Deskstar 7K1000). The current capacity champion, Seagate’s Barracuda 7200.11 at 1.5 TB, reaches its capacity point using four platters.

You can find out the platter count by looking at the number of heads, which is always listed in a hard drive’s data sheet. Every platter requires two read/write heads: one for the top and another for the bottom. Eight heads, for instance, means that there are four platters.

Spindle Speed

Most fast desktop hard drives use a 7,200 RPM spindle speed. Some low-power options, such as the WD Caviar Green series or the Samsung Eco Green drives, spin at a reduced 5,400 RPM rotation speed, which introduces power savings at the expense of performance. However, a modern and well designed 5,400 RPM drive may very well compete with an average 7,200 RPM drive. Clearly, it’s important to always go for the most recent product, to be sure you get the best bang for the buck.

An important drive to mention in the context of spindle speed is Western Digital’s Raptor family, which has thus far been the only 10,000 RPM desktop hard drive. The first-generation models, with capacities of up to 150 GB were based on the 3.5” form factor, while the latest product, the Velociraptor, is a 2.5” drive meant to also fit into the entry-level enterprise segment. While the Velociraptor is the fastest mechanical desktop hard drive, the older versions are only faster than modern terabyte drives when it comes to I/O performance and access time. Throughput is higher on any of the mainstream 7,200 RPM 3.5” drives today.

Negligible Details

Drive manufacturers and PC vendors sometimes advertise the cache size of a hard drive: 32 MB currently is the largest cache size right now, 16 MB can be considered the de-facto standard, and some lower-capacity drives still come with only 8 MB of cache. It’s worth noting, however, that we looked at the difference between 8 MB and 16 MB cache in 2007 and found no significant difference.

The drive’s interface is another technical detail that is almost negligible. Nearly all desktop hard drives are based on Serial ATA/300, while notebook drives utilize SATA/150 or SATA/300. Since desktop hard drives have not even reached 130 MB/s in throughput, even SATA/150 would be fast enough for all models currently available. SATA/300 makes sure that cache throughput is maximized, but it does not make a noticeable difference in everyday use. So go ahead and attach a SATA/300 drive if you only have a SATA/150 controller—it won’t introduce a serious performance penalty today. Making the jump to SSDs, of course, puts more of an emphasis on interface.

Cost And Warranty

Warranty is not only important for getting a replacement in case of drive failure. Because you intend to use your new hard drive for several years, and we’re talking about rather high capacities of a terabyte or more, a solid warranty creates confidence. We wouldn’t want to spend money on a 1.5 TB hard drive that comes with a poor one or two year warranty. Fortunately, all hard drive makers provide at least three years’ warranty for their retail products. All premium desktop drives, as well as all enterprise drives, are backed by a five-year factory warranty. This applies to Seagate’s Barracuda 7200.11 family and to the Western Digital Caviar Black series as well.

Be careful if you purchase an OEM drive that wasn’t intended to be sold separately: these may be covered by shorter warranties.

Finally, we recommend checking the cost per gigabyte once you select your hard drive type. If you don’t really need a full terabyte of storage, you can save money if you go for a “sweet spot” capacity. Most likely, the 750 GB or 640 GB version of the desired drive offers a better cost per gigabyte than the terabyte top model.

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  • 0 Hide
    slomo4sho , November 24, 2008 7:19 AM
    Thanks for the write-up.
  • 0 Hide
    Tindytim , November 24, 2008 8:05 AM
    I would be interested in seeing how SSDs have effected Raptor sales.
  • 0 Hide
    radnor , November 24, 2008 9:02 AM
    I honestly think SSDs wont touch Velociraptor sales. The price tag is just too different. Even 300Gb is kinda short. Not to mention 64Gb.

    SSDs for now are only rich lappy owners. For the rest, there is SAS.
  • 0 Hide
    arkadi , November 24, 2008 10:45 AM
    with the new x58 out, it will be nice 2 see how sas drives will do
  • -1 Hide
    slomo4sho , November 24, 2008 11:10 AM
    There are 30gb OCZ SSDs on newegg for $80 each. Anyone wanting a faster drive for the OS would definitely consider the SSD over a Raptor.
  • 3 Hide
    DFGum , November 24, 2008 11:12 AM
    Slomo4shOThere are 30gb OCZ SSDs on newegg for $80 each. Anyone wanting a faster drive for the OS would definitely consider the SSD over a Raptor.

    Except there not faster.
  • 2 Hide
    zenmaster , November 24, 2008 11:12 AM
    Have you seen the OCZ horror stories?
  • 1 Hide
    antiacid , November 24, 2008 12:38 PM
    SSD doesn't equate to better performances than raptors. Watch out for that :) 

    thanks for the review, it's nice to see the Hitachi's getting updated to such fast drives.
  • 3 Hide
    neiroatopelcc , November 24, 2008 12:48 PM
    EcoGreen F1 @ -60C operational temperature? That may not be the most ideal enviroment to run a pc ? might want to add a zero in front :) 

    ps. no noise measurements?
  • 0 Hide
    Anonymous , November 24, 2008 1:05 PM
    yes, no noise measuring? That is a important as anything else for a HTPC?
  • -1 Hide
    malveaux , November 24, 2008 1:17 PM
    SSD's aSSD's, especially the MLC ones, are not effecting gaming machine sales (raptor). They're terrible for PC's right now that run Windows. They're better than their initial release. But they're still not something to overtake the markget for a while.
  • 6 Hide
    chikatana , November 24, 2008 4:27 PM
    The gallery thing is so user unfriendly. I hate it so much since its introduction. It takes much longer to load, and I have to switch between browser windows constantly to see all the images. Please go back to the old design and show all the images in a few pages directly. I don't want to keep switching!!!
  • -1 Hide
    Pei-chen , November 24, 2008 4:42 PM
    I am using two 1.5TB drive in RAID 0 under Vista x64 and it doesn't feel any faster than the two 320GB 7200.10 RAID 0 drives it replaced. The throughput for the 320GB is 70 MB/s or 140 MB/s on RAID 0; the 1.5TB should be noticeably faster but it isn’t.

    BTW, the maxima drive size windows can address is 2TB so my 2*1.5TB shows up as one 2TB + one 700GB drives.
  • -1 Hide
    Eggrenade , November 24, 2008 7:46 PM
    This is one of those articles that reminds me why I like Tom's so much: quantitative comparisons that are useful.
  • 0 Hide
    JonnyDough , November 24, 2008 8:55 PM
    Quote:
    Properly-designed flash-based solid state drives are not only faster than conventional drives, they can also require considerably less power


    LMAO! A couple of months ago Tom's had an article saying that the energy-saving of SSDs was a hoax. The title even had the word "hoax" in it. I called their bluff, and got down-rated in the comments on that article. Now, they're saying the exact opposite! How many times does Tom's say one thing to spark controversy and get website hits, and then say the exact opposite later on? This website is SO FULL OF CRAP.

    5...
    4...
    3...
    2...
    1. Post deleted like APPLE owns this site.
  • 1 Hide
    JonnyDough , November 24, 2008 9:03 PM
    SSDs ARE faster than HDDs, IF you have the right SSD. Furthermore, that is not the ONLY advantage to having an SSD. Heat, energy use, ability to handle more shock, and noise all contribute.

    XP and Vista is not correctly optimized for SSDs, but that doesn't mean that a high end SSD won't outperform hard drives on them.
  • 1 Hide
    doomsdaydave11 , November 24, 2008 9:33 PM
    DFGumExcept there not faster.

    Yeah those cheapo OCZ (etc) drives are incredibly slow. My next harddrive will be a 500GB Seagate 7200.11. That should last me at least 2 years, and then I'll go with maybe a 512GB SSD or something. Surely they'll have 512GB SSD's that provide at least 200MB/s read and 150MB/s write at a reasonable price in 2 years.... especially with all these memory prices dropping. Last year you could get 2x2GB of DDR2-800 for ~$200. Now, 2x2GB of DDR2-800 can be had for under $50, and even lower then that after rebates!
  • 0 Hide
    Anonymous , November 25, 2008 12:09 AM
    The WD Raptor 36GB and above can still be used within a raid-0 array. Heck thats what i'm using now, i was looking for SSD's but too much SSD's that have their issues and wont come down at least for 350€ for a decent Raid-0 set.

  • 0 Hide
    Anonymous , November 25, 2008 2:13 AM
    I checked Newegg and noticed that the following drives aren't readily available, yet Tom's is recommending them. What's up ?

    Hitachi 7K1000.B
    Seagate new 1TB
  • 0 Hide
    Codesmith , November 25, 2008 4:01 AM
    I look at not only the length of the warranty but the quality of the support. When my seagate failed I had to pay a total of $27 for advanced replacement. When my western digital failed advanced replacement was free and I only paid $7 for a optional prepaid return shipping label.

    Also I had to get to page idk 17 or 19 in the RMA process before I saw anything about an advance replacement fee.

    I am not saying I won't ever buy a seagate, just saying I lean heavily toward WD because of the way they handle replacements.

    I wish I new all the manufacturers policies on advance replacement fee's. But one's that charge don't advertise it so I am kinda in the dark.
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