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Will the full speed advantages of the future USB 3.0 be negated by the fact the most HD being mass produced are SATA 3? If so, what would you suggest a person do? For performance reasons, I go with eSATA or 1394 for external hard drives.

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closed as not constructive by Sathya May 20 '11 at 3:30

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I think you mean SATA 2, not SATA 3. SATA 2 operates at 3Gb/s and SATA 3 will operate at 6Gbp/s –  MDMarra Sep 28 '09 at 22:15
Wikipedia describes it as SATA 3 Gbit/s (Second generation) and SATA 6 Gbit/s (Third generation) respectively. –  Robert Nickens Sep 28 '09 at 22:38
The 3 is tied to the Gb/s. Saying SATA 3 without the units after it is confusing and not right. SATA 2 (the second generation spec) operated at 3Gb/s, this is not the same as saying simply SATA 3 –  MDMarra Oct 2 '09 at 4:06
@MarkM it's normally written "SATA II" instead of "SATA 2", so "SATA 3" can be assumed to mean "SATA 3Gb/s". –  quack quixote Oct 3 '09 at 21:00
This is the first time I've heard "SATA II" be referred to as "SATA 3". –  Travis Dec 7 '09 at 16:34

9 Answers 9

Well, I would go with Esata if you can, simply because it would be almost the same as directly plugging a hard drive straight into your machine as a normal hard drive.

USB is universal by name, it is meant for pretty much any and every device you can imagine. Whilst I doubt there would be any big speed issues, there is no point in using it if you can support Esata.

All of this is just based on my experience, can't really say anything for sure as the technology has not yet been released.

The fact is, USB to ethernet adapters work, but a standard ethernet card is faster, usb keyboards work - but most of the time, ps/2 keyboards work more "natively".

At the end of the day USB hard drive works, but you will be converting a perfectly good SATA signal to USB, when esata is basically just connecting a external hard drive directly to the motherboard in the same way as a internal hard drive.

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Very well said. To extend your answer - why share the USB bus with other devices when you can mainline directly into the sata connector? –  JL. Nov 9 '10 at 18:23
According to wikipedia eSata standard is still limited to 3Gb/s speed. Do you know if this is still the case? USB 3 is 5Gb/s. If both these are true then surely USB 3 would still be higher throughput. –  Matt H Jun 23 '11 at 2:04

One factor to consider is access to SMART data. In all the HDDs I own, SMART data is not accessible over USB. HDD manufacturers will support SMART over USB3 in future. but if you want to check your HDD SMART data now I'd stick with e-SATA.

For HDDs on the market today (April 2011), you can typically use two HDDs per e-SATA connection before maxing out the bandwidth.

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I'm not quite sure what the dilemma is...

Most motherboards come with at least on eSATA port and several USB 2.0 ports these days, so if you can get external devices that support eSATA you are better off. As USB 3.0 is adopted, motherboards will continue to offer eSATA ports alongside USB. So any kit you have now will be at least as capable then as it is now. But there will be a delay before USB 3.0 kit comes through anyway, so the decision as to whether to jump from eSATA to USB 3.0 is not one you need to make now. And by the time you are in a position to decide, the route may be a whole lot more clearer.

NOTE: For the time being, eSATA is still faster than USB3....

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usb 3 is 6gb vs esata 3gb

usb 3 supports data+power vs esata requires a separate power adapter

so unless esata starts supporting more bandwidth and power, its win for usb 3

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A nice theoretical answer –  JL. Nov 9 '10 at 18:28
Except that SATA is also available in 6Gb/s bandwidth (SATA III) and is usually combined with a USB connector to form eSATAp to provide power (and maybe USB data as well). –  Mircea Chirea Jan 2 '11 at 20:21

I don't think this is a fair comparision talking about the standards in general as USB 3 is intended to support many devices and not just hard drives. SATA is only a hard drive standard.

If we are just talking hard drives, we will see how well USB 3 does with the overhead of multiple devices on the bus. None the less, regular hard drives have not even saturated sata2 theoretical throughput, let alone the future standards (single mechanical drives, not raid). So the same drive today on sata2 is going to perform exactly the same on sata3. However, SSD drives are pushing past sataII and will need the new SATA 6gb/s performance. Check out this new drive coming soon (up to 355Mb/s reads): http://www.micron.com/products/real%5Fssd/ssd/client/index

I would not go out of my way to make sure everything was USB 3 on a new setup until it becomes more common place and devices support it. I also do not plan on replacing every external hard drive on usb 2 I have right away, so I don't think it is worth the cost at the beginning. I guess it really depends if you are buying a new computer and you either have very few accessories/external devices or you have many to support. I would weigh the pros/cons of spending the extra cash and what devices you have that could potentially use it.

Whatever your decision, there will always be an expansion card available.

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SSD are already SATA2 (and SATA3) bandwidth limited when doing seq transfers –  Pyrolistical Sep 28 '09 at 21:47
I knew we were getting close, but I haven't seen any benchmarks that showed a single drive hitting sata2 saturation. If you got a link, that would be cool to see. –  Troggy Sep 28 '09 at 21:54
Pretty much all second gen SSD that hit 262 MB/s. That's the real world SATA2 limit: pcper.com/comments.php?nid=7527 –  Pyrolistical Sep 28 '09 at 23:49
@Pyro: Well, SSD performance is just skyrocketing faster than I ever thought. Check out this new SSD coming soon with up to 355Mb's reads: micron.com/products/real_ssd/ssd/client/index –  Troggy Dec 7 '09 at 16:11
Its all very well talking about SSD's but remember the e in eSata stands for "External". In 5 years from now the general public might be able to afford External SSD's, not at the moment. Another thing to consider is eSata is not host powered. While USB 3 is. –  JL. Nov 9 '10 at 18:25

not for hard drives.

eSATA is isochronous, USB is not. Hard drives operate on SATA, thus SATA is always going to be fastest. USB2 had a 480Mbit transfer rate, but HDD's rarely exceeded 240Mbit.

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HDDs rarely exceeded 240Mbit? That's 30MB/s. HDDs are three times faster than that typically. –  Mircea Chirea Jan 2 '11 at 20:24

The USB2 interface has a theoretical max of 480Mbit/s=60Mbyte/s (MB), and in practice rarely faster than 30MB/s, whilst the fast SSD harddrives has about 240MB/s transfer rate, NOT 240Mbit.

I think the only thing actuall differing USB3 from eSATA in practice is power over the same cable, which was mentioned earlier, as this makes USB3 much easier to handle when using portable hardrives and such. Also, the fact that its backwards compatible with USB 2/1 which makes any usb3 unit usable on older systems aswell is a big plus.

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Beware you can't install and boot an operation system on USBx hard drive but you CAN install and boot any system on eSATA drive. With eSATA you can use single portable system (even Windows 7 licensing issues aside) in both office and at home without any speed or comfort sacrifice.

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You haven't heard of USB booting yet, have you? –  Mircea Chirea Jan 2 '11 at 20:22

Only on older motherboards you cannot boot from USB, and I've indeed run an OS (FreeBSD) from USB memory stick. Possibly you need to enable boot from USB in the motherboard's BIOS.

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