Need New external HDD: Platter Density (need explanations! (Dumbed down))

Discussion in 'MacBook Pro' started by iMackPro, May 1, 2011.

  1. iMackPro macrumors 6502

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    Mar 31, 2011
    #1
    Ive been looking to buy an External HDD. I need around 1TB of storage, id be willing to get any amount of storage between 0.750-1 TB of storage.

    I recently have discovered that there are many many differences that will help the I/O speed of a plattery drive. Besides the RPM of the drive i undertaand that the platter density plays a big role when it comes to transferring data and loading movies and whatnot. i Have MRoogled and Googled have came up with only a few webpages about what Platter Density is and i couldn't quite grasp the concept.!!!!! This is where all of you very intelligent members get to help me!

    So i think (in a very very tight nutshell) that plattery density means how (Dense, for lack of better word lol) the platter is. (god that sentence makes me sound so stupid) or like how compact the Platter is and therefore it can find stuff faster and load fater? so apparently i want a very high density platter for speed!? or do i have this entirely wrong and a dense platter means that everything is crammed together and you DO NOT want a dense platter HDD if you are looking for speed?
    If you are not going to read the above please read and respond to this. I only have about 300$ and i REALLY NEED an EXTERNAL HDD. NOT SSD. i need it to be very quick. im willing to sacrifice space in order for more speed (ie get a faster 800GB opposed to a slower 2 TB or something like that) ALL i want to use this drive for is games and BLU-RAY discs. i have about 90 gigs on my other external but ITS SO INCREDIBLY SLOW.
    Can anyone recommend for me, and everyone else out there a drive that is very very fast? Im looking for one of the fastest EXTERNAL HDDs that money can buy (within a $300 price range!) Noise doesn't bother me and if you can find me a really fast eHDD and its noise i don't care, also if it has to be plugged into the wall, again i don't care.

    All i want is an external HDD that i can store hundreds and hundreds on, but again i want to be very very fast so that it can transfer the movies from my external HDD to my macbook to stream on my TV, via moshi MD-->Samsung 60 inch Plasma =). I have read reviews about 10k and even 12k RPM hard drives? should i look into these? Also, this thread is for anyone and everyone that needs a one stop shop for buying quick and higher end HDDs.



    THanks to anyone and everyone that helps me out on this! i know im not the only one that needs a speedy HDD for the transfer of movies!!!
     
  2. mape2k macrumors regular

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    #2
    Data is stored on a hard-drive platter in 1 and 0 (bits). Now you imagine the platter as being a sum of little cells, each able of containing a 1 or 0 (depends on what data is written). The platter density is the distance between those cells. Higher densities mean lesser distances between the cells and therefore more data can be written on a given length of platter.
    Since the hard drive platter is a spinning device, higher density means naturally that more data can be written in a given time (more cells pass the reading head).

    I would recommend a Western Digital VelociRaptor (600GB cost about 180$) and an external enclosure of your choice (preferably with FW800 or USB3). That is, to my knowledge, a very fast drive.
     
  3. iMackPro thread starter macrumors 6502

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    #3
    thank you very very much kind sir, or ma'am. i will look into it, 180 bucks is way cheaper than i thought, so yo are saying that i indeed DO WANT a hdd thats high in platter density correct? also, im looking at bestbuy and its not showing me what the platter density is? Should i wait until thunderbolt? i don't want this wicked fast HDD and then it being all bottlenecked up because the damn cable cant transfer the data as fast as my drive is reading the data.
     
  4. iMackPro thread starter macrumors 6502

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    #4
    29 views and no one can help me find a top of line HDD?
     
  5. mape2k macrumors regular

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    #5
    That would be a sir ;)

    Yes, you want the higher platter density. Until now, I did not see it in any shop description of a HDD that I have read. You would have to get into reading reviews of the HDD you want (like this one from anandtech) where they show a 200GB/platter density of the velociraptor. Another review of the drive is here. Both state that the drive is in fact the fastes SATA platter drive you can buy.

    Anandtech shows a peak reading speed of about 140 MB/s. FW800 supports up to 400MB/s, so you should be fine with a FW enclosure. Thunderbolt is nice, but it will take some time until the first 3,5" enclosures with TB will appear on the market... I don't think its worth the wait.
     
  6. systole macrumors member

    systole

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    #6
    Another Consideration

    While density aids R/W speeds, make sure whatever drive you buy has at least a 32MB cache, if not 64MB.

    Also take a look at the WD 640GB Caviar Black. It has 320GB/Platter if your going for pure density, and it is a very, very, solid 7200k drive. I have two that I have been using in a Raid-1 array with a dedicated hardware RAID card. Couldn't be happier.
     
  7. cube macrumors G5

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    #7
    You need to look around the internet to find out the platter density.

    Either you'll find the explicit number or you will find how many platters the drive consists of.

    For example, you can find that a drive has 667MB platters, or that it's a 2TB drive with 3 platters (2000/3 = 667).

    All other things being equal, less platters means higher reliability, too.

    Regarding 3.5":

    - Samsung has 1000MB platters in prototype. When they come out, expect it to be on "green" drives (ie, low RPM).
    - 667MB or 750MB platters are still only on low RPM drives.

    2.5" drives will have lower numbers than these, of course.
    I don't know that's the state of the art in 2.5" or 7200 RPM drives.

    A number that will guide you in the search for a quick drive is "access time". You can find this on every spec sheet. Smaller is better, of course.

    I don't think the amount of cache is very important (except when talking about a hybrid disk's flash memory).
     
  8. CorporateFelon macrumors regular

    CorporateFelon

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    #8
    Top of the line means money.

    Honestly I think any modern eternal will do you fine. Also for the amount of space you're looking for there are tons of options for well under that price range.

    http://www.newegg.com/Store/SubCategory.aspx?SubCategory=414&name=External-Hard-Drives
     
  9. Hellhammer Moderator

    Hellhammer

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    #9
    The biggest issue is not the speed of the drive but the interface. USB 2.0 can only provide around 35MB/s in real world. Any decent HD should be able to provide that. 2TB drives can often provide 120MB/s or so.

    If you want something fast, wait for Thunderbolt devices to hit the market. This should happen in two months (OEMs have said Q2). It can provide up to 10Gb/s which is way more than USB 2.0 or FW800 can provide. You should be able to get 2x2TB in RAID 0 for 300$, although the prices of TB devices is still a big unknown (2TB HDs are less than 100$ each so I would bet that you can get an enclosure for 100$).

    FireWire 800: 800Mb/s = 80MB/s

    375GB is the densest platter 2.5" drives. Available in 5400rpm and 7200rpm flavors and found in e.g. 750GB Scorpio Black.
     
  10. snaky69 macrumors 603

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    #10
    I didn't bother reading your post, but I am going to answer anyway.

    The problem is not your external hard drive being slow, it's the interface you use to plug it in that is slow. I assume you're using it with USB 2.0 which is just about the slowest interface you can use for a hard drive.

    I'd look into a FW800 enclosure if your macbook pro has the port, and if you have an expresscard slot, I'd look into and esata expresscard and esata enclosure, much, much, much faster than USB.
     
  11. cube macrumors G5

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    #11
    The biggest issue with hard drives is not the transfer speed but the access time.

    A higher density platter means the arm needs to seek less to access nearby blocks.

    But yes, to fully utilize an external drive means ExpressCard (eSATA) or Thunderbolt.
     
  12. nampramos macrumors 6502

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    #12
    I would like to use this thread to ask something also.
    I am going to upgrade my MacBook hard drive and will then have a spare 160GB hdd.
    I want to buy a enclosure for it. Does need eSATA or FW. USB 2.0 is enough.
    Can someone recommend me one?
    Thanks.
     
  13. cube macrumors G5

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    #13
    Even FW400 is faster than USB 2.0. It's not too shabby.

    The two brands of enclosures that I have are OWC and Macpower (now inXtron). I normally look for OWC first, but this Macpower ended up being very nice.
     
  14. Hellhammer Moderator

    Hellhammer

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    #14
    Depends on the usage. OP said the most important thing for him is that the drive is fast at transferring movies from the external to his MBP, so what he wants is high sustained transfer speed. Seek time doesn't really matter with that.

    All in all, when the density increases, sustained speeds increase too and the seek time decreases. I wouldn't go with anything less than 1TB, they are so cheap nowadays.

    What will you use it for? For most things, USB 2.0 is more than fine. eSATA is only available via ExpressCard slot so that is out of question for most people. FW800 is faster than USB but costs a premium.
     
  15. firesong macrumors member

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    #15
    USB sucks for sustained transfers - they're only fast Burst.

    Go with Firewire800 at least, while waiting for Thunderbird enclosures. You can always transfer the drive over to a TB enclosure.

    In the meantime, just get any drive you fancy. You'll generally find the bottlenecks at your interface for USB2.0/3.0, and at the drive for FW800/Thunderbird.
     
  16. nampramos macrumors 6502

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    #16
    I have a MacBook 5,1 so no FW.
    That´s why I said only USB.
    I would like a small case, that basicly is only a bit bigger than the hdd itself and preferably in alluminium.
     
  17. mape2k macrumors regular

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    #17
    In that case you will be happy with a inXtron SK-2500 2.5" enclosure.
     
  18. nampramos macrumors 6502

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    #18
    It looks bigger than other enclosures I´ve seen. Can it be only from the picture or it is actually a bigger case?
    Also, can I buy that in Europe or only in US?
    Thanks.
     
  19. cube macrumors G5

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    #19
    You can buy Macpower/inXtron in Europe, but it also looked to me that that case is bigger than what you're looking for, that's why I didn't suggest the OWC mini.

    I don't know if you will find any good tight fitting cases.

    If 250GB is enough, you may try finding a 1.8" USB case and put a Toshiba in it. I think I saw some vendors in amazon.com. Be careful that it be one with the correct internal connector.
     
  20. nampramos macrumors 6502

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    #20
    I already have the hdd.
    Its the one I had inside my MacBook before.
    A 2.5'' 160GB.
    So now I only need the enclosure and it needs to be sold in Europe aswell.
    I dont need no fancy connections. Just USB 2.0 and I would like it to be small and in alluminium.


    By the way, I formatted a USB Stick from Sandisk today and it is still formatting. Its been more than 6 hours now. Size is 16Gb. Is this normal or something is wrong? And it says that it is still 10 hours left, though that time has been still for a long time. I'm formatting it to FAT.
     
  21. gr8tfly macrumors 603

    gr8tfly

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    #21
    I fell asleep while writing this last night when your OP popped up. It's been answered by others between then and the time I saw daylight again, but since I bothered writing it, I'll post it anyway: ;)

    None of those specs will matter if you use USB 2 as the interface (which, I suspect could be your bottleneck.)

    To get the most out of a single 7200 RPM drive, you will need to go with FW800. eSATA is faster, but you would need to use an ExpressCard adapter, and it's more difficult to interface with multiple drives. Whereas FW can be daisy changed with zero configuration. I currently have 4ea. 1TB and 1ea. 750GB on a single FW800 chain off my Early 2009 17" MBP. I also have an internal 500GB 7200 Seagate XT and get up to 70MB/sec. transfer rates using Finder copy to the FW drives. Most current desktop drives can exceed even FW800's bandwidth for a single drive, but will help quite a bit when you are moving data between drives on the same chain.

    Density refers to areal densitity usually expressed in bits/sq. in. on the single surface of a platter. A platter with higher areal density (which most larger capacity drives will have) can access more data on a single track. Since the head doesn't need to seek as often, the throughput increases. Those specs are available through the drive's manufacturer's data sheets.
     
  22. davidlv macrumors 65816

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    #22
  23. Prodo123 macrumors 68020

    Prodo123

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    #23
    You are correct about the density of the platters; however you are wrong about its effect. If the platters are dense, then more data can be crammed onto the platters.
    Technically the fastest external HDD out right now uses USB 3.0, which is not supported, so the next best is FireWire 800. LaCie has some good ones, like that.

    Also, why not go for a server and stream movies?
     
  24. iMackPro thread starter macrumors 6502

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    #24
    my way seems cheaper and easier? if you can sell me on id look into it! im all about quick and simple. would you mind furthering your explanation about me using a server for streaming movies ?
     
  25. iMackPro thread starter macrumors 6502

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    #25
    whats the cache going to do for me while i want to move large files around?
     

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