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external drive charts

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June 12, 2006 4:09:03 AM

Am I correct that there are no interactive comparison charts for external hard drives? Where can I find this information?

More about : external drive charts

June 12, 2006 4:42:47 AM

whhy do you need it?

it all depends on how fast ur connector is...

usb 2.0 = 480 mbps

sata connector = 3 gbps

firewire = i forgot
June 12, 2006 3:04:22 PM

Unfortunately you will have to find a review for each drive you are interested in.

If you don't need one touch backup you are probably better off simply building one yourself. The HD usually has a much better warranty than the enclosure, you will be able to update the enclosure by adding a larger drive ....



PS here is a speed chart for just about every standard.

http://amdg.no-ip.org/slackware/slackstuff/speedcharts.htm
Related resources
June 12, 2006 8:12:34 PM

Thank you for the suggestions. To reiterate, you say to buy an internal drive and mount in an enclusure. Is the quality then better than a manufactured external drive? And, assuming I buy a drive, enclosure, cable, and card to get into a laptop, will there be a large difference in cost?

Thanks also for the link.

Regarding why I need this and the transfer rates: I need to backup my laptop and maybe backoff some data. There are fifteen performance measures for comparing the internal hard drives and no such comparisons available for external drives. I had not considered building my own, but maybe I could get a better drive for a competitive price by doing so (see questions above). Anyway, I understand that no drive is perfect, so it seems intuitive that the test batteries apply equally to the external drives.

It would seem a shame not to get a SATA connection option (I am pretty sure the true spec eSATA). To get SATA bundled with USB and/or firewire would be desireable for the flexibility. My laptop will need a card to make the SATA connection (firewire also). Does this reduce the transfer rate?
June 12, 2006 8:34:38 PM

my opinion for you:

1) get sata and usb... i mean, even if you cant use sata now, theres always a later date.

2) firewire sucks compared to usb2
June 12, 2006 8:41:10 PM

Well, your right in thinking youll get higher transfer rates with and external drive, but remember you rates (even to page files) will only be as fast as your current drives burst rate. Which is my next point, dont get hung up on the interface. 150 Trasfer rates are not going to be achived in reality becuase all those numbers are burst rates in a vaccume.

If you looking for a quick solution you can get an SATA PCMICA card and the enclosures here, I would reccomend something like this for max strage, but the come with single bays http://www.cooldrives.com/mi3sadudrale.html

Your total cost depending on size will be just shy of 200 bucks.

They do sell cards for PCMICA that have all three interfaces or just two of your likeing. Just remember when looking at it from a price stance. PCMICA on laptops are usually 32 bit, almost he same as a PC, which run at 33mhz, with a steady transfer rate of 132mb's.
June 12, 2006 8:45:14 PM

Quote:
my opinion for you:

1) get sata and usb... i mean, even if you cant use sata now, theres always a later date.

2) firewire sucks compared to usb2



80mbps Diffrence which is only burst speeds. So your basing it on that you dont own a camera or what? In this case the cheapest solution makes the most sense if he is getting a card, but I agree you can get all the interfaces on card for future use, but just remeber you can only go as fast as your bus will allow.
June 12, 2006 9:53:48 PM

Quote:
Well, your right in thinking youll get higher transfer rates with and external drive...

Wouldn't the internal drive be faster (not that I have a choice to back up a laptop)?

... dont get hung up on the interface. 150 Trasfer rates are not going to be achived in reality becuase all those numbers are burst rates in a vaccume.

Thanks. But, will eSATA will outperform firewire 800 and USB 480, or will all get knocked down to 132 mbps as you suggest below?

If you looking for a quick solution you can get an SATA PCMICA card and the enclosures here, I would reccomend something like this for max strage, but the come with single bays http://www.cooldrives.com/mi3sadudrale.html
Your total cost depending on size will be just shy of 200 bucks.

Thank you for this info. Three types of product solutions seem to be: a manufactured external drive, an internal drive mounted in a case, and a case with removeable hard drives (hybrid?). Is there any difference in the drive itself or the interface? The only advantage I forsee for the removeable drive is to transport easier if I travel to a place that has compatible slots (might not need or be able to take advantage).

They do sell cards for PCMICA that have all three interfaces or just two of your likeing. Just remember when looking at it from a price stance. PCMICA on laptops are usually 32 bit, almost he same as a PC, which run at 33mhz, with a steady transfer rate of 132mb's.
June 12, 2006 10:24:26 PM

Quote:

2) firewire sucks compared to usb2


That seems a bit harsh... and at least in my experience completely wrong. Sure Firewire has a lower theoretical transfer rate than USB 2.0 (400Mbps vs 480 Mbps), but Firewire is much better for streaming large amounts of data whereas USB has to put everything into packets to send it across the bus. This results in higher CPU utilization, extra latency, and overall more overhead. If course it all depends on how efficient the controller in the computer is as well as how efficient the USB/Firewire to ATA bridge is, but in my experience with several enclosures, drives and computers, Firewire will be between 5-10MB/s faster than USB 2.0, with much less CPU utilization, and slightly improved latencies. I remember posting about this before, and I ran a suite of tests using HD Tach and posted my results... I'll see if I can find it.

That in mind, Firewire enclosures tend to cost more, and most computers and enclosures don't have Firewire (1394a) let alone the faster Firewire spec (1394b) USB is more practical in most cases. Plus, if its a 3.5" enclosure the performance will probably leave a 2.5" internal drive in the dust anyway.

-mcg
June 12, 2006 10:42:17 PM

I found my old post:
Quote:
here's the data I gathered using HD Tach:

USB 2.0: random access 15.3ms, Avg read: 22.9 MB/s, burst speed: 29.1 MB/s

Firewire: random access 15.0ms, Avg read: 31.0 MB/s, burst speed: 40.4 MB/s

Also: just Google'd up "firewire vs usb" (without the quotes) and got this:
http://www.usb-ware.com/firewire-vs-usb.htm
This article is older, but shows pics of transfer diagrams:
http://www.digit-life.com/articles/usb20vsfirewire/


Those tests were done using a Seagate external enclosure and a 120GB Seagate 7200.7 drive on my Asus Z71V laptop (Intel i915PM chipset). I have since also run the same tests using the same drive/enclosure on an Asus A8N-SLI Deluxe board and got similar results. I also have tried an "ULTRA" enclosure with a WD 7200 RPM drive on both platforms and got the same trend, but higher speeds on both (probably since the Seagate Firewire/USB2 to ATA bridge is several years older).

Also of note, based on the transfer diagram it looked like USB 2.0 was allowing the drive to become interface bandwidth (hitting a flat ceiling) over the majority of the drive whereas with Firewire there was much less interface limiting.

-mcg
June 12, 2006 10:47:02 PM

There are two extrenal SATA standards in practical use, and they are mechanically and electrically different.

At first the SATA board didn't produce an external standard, but since internal cables can run one meter, people just made products using the internal conneciton.

Then there came eSATA from the SATA board. It offeres lengths of two meters and to do so changes the electrical characterstics. Each device sends a more powerful signal and has to except a weaker signal. Since they are not 100% electrically compatiable and to avoid confustion eSATA was made mechanically imcompatibe.

Most enclosures and SATA use intenral SATA as do most SATA cards, others use eSATA.

I use a PATA to USB 2.0,SATA enclosure. I can buy an adpater that will create an external SATA port, but I just use a long SATA cable hanging out the back of my PC.

The SATA port gives me 100% of the drives performance, USB 2.0 is for connecting to PCs without an external SATA port.
---
I am guessing about the benifits of building it yourself so you should check. I never even considered doing it any other way.

I like the freedom to chose whatever drive I want, replace either the drive or the enclosure if it fails ...

Plus I have a bunch of old 40 & 120 GB PATA hard drive going to waste.
June 12, 2006 11:06:23 PM

Quote:
my opinion for you:

1) get sata and usb... i mean, even if you cant use sata now, theres always a later date.

2) firewire sucks compared to usb2


"firewire sucks" thats complete nonsense, dont be fooled by the *extra* 80Mbps that USB2 claims, since in all the cases and benchmarks iv tried, the sustained transfer on firewire is far superior to USB, by a massive margin. On my external FW drive i get a good steady 38MB/s close the the max of 40MB/s

I forget the exact results, but in all cases i experimented with USB2 never got close to the 48MB/s theoretical maximum, and nor did it get close to the performance youl get with FW. I tried this with a number of drives and a number of different machines, to rule out poor USB cards or similar problems. FW always came out on top

So, in sumary, go with a FW drive. If you have an FW800 port even better, although bear in mind any transfer rates will be limited by the speed of the source yource copying from.
June 12, 2006 11:47:26 PM

USB thrived over firewire for bussiness reasons, like VHS thrived over Betamax. Firewire 400 outperforms USB2 (480), and firewire 800 doubles performance again.

Unfortunately, my laptop has USB2, so I think I have to port SATA or firewire through a card if I choose that route. Will all standards be reduced to the same 132 mbps (as asked above)?

An internal SATA connection is not available on laptops is it? I am still not clear about the differences between mounting an internal drive in an enclosure, a manufactured external drive, and an external system with removeable drives in slots. Anyone?

My questions are regarding speed and reliability, but again, why are the same 15 performance criteria in the drive charts not applied equally to external drives?
June 13, 2006 3:36:34 AM

After reading everything you've posted I think that a USB enclosure will do you fine. If I understand correctly, you want to use the external HD to backup data from your laptop. In this case, your laptop's hard drive will be the limiting factor, not the connector you use for connecting the hard drive. Using my laptop's drive as a baseline (a Seagate Momentus 5400.1) the laptop's transfer rate should rarely if ever exceed what USB 2.0 can pull. My laptop's peak sustained (not burst) transfer is a bit less than 35MB/s and one of my two external enclosures is capable of 34.0 MB/s over USB 2.0.

Also, I'm not sure if you realize it, but "external" hard drives ARE internal hard drives... but with an external enclosure and a USB2.0 and/or Firewire bridge. If you already know this and you feel that I am insulting your inteligence I apologize. This is not my intention. Anyhow, the efficiency of the bridge and the efficiency of the USB or Firewire controler in the computer affect how much of the drive's potential can be utilized. This could be why there aren't any charts for external drives since not only the drive used, but the bridge and the controller on the computer all become factors in how fast the drive is. Perhaps a chart of the peak bandwidth different bridges can provide would be practical, then people could match a drive to a bridge that would meet their needs.

Lastly, you can save a lot of money building your external drive yourself. You also get the flexibility of being able to choose whatever drive you want, and have the option of (relatively easily) upgrading it later. I haven't checked, but I think that USB2.0+Firewire enclosures run about $30. Add to that the price of whatever drive you want, and that's your price. Manufacturers usually charge a hefty premium for their external enclosures, and I would venture to say that in most if not all cases, building your own will be significantly cheaper.

I guess I should also mention that (assuming I got your usage right) you shouldn't need to bother with buying a FW or SATA card, making the POSSIBLE (I honestly have no idea) 132Mbps cap irrelevant.

Hope this helped! I'll keep my eye on this thread, so post back as to whether this answered your question. :D 

Edit: I guess I didn't read THAT carefully... If you read my whloe post you'll realize that. Also, some laptops (mine included) have internal SATA conectors, but they're for 2.5" drives, not 3.5" desktop drives so that still wouldn't really matter.

-mcg
June 13, 2006 9:18:22 PM

Quote:
After reading everything you've posted I think that a USB enclosure will do you fine. If I understand correctly, you want to use the external HD to backup data from your laptop. In this case, your laptop's hard drive will be the limiting factor, not the connector you use for connecting the hard drive. Using my laptop's drive as a baseline (a Seagate Momentus 5400.1) the laptop's transfer rate should rarely if ever exceed what USB 2.0 can pull. My laptop's peak sustained (not burst) transfer is a bit less than 35MB/s and one of my two external enclosures is capable of 34.0 MB/s over USB 2.0.

My Thinkpad R52 is not with me today, but the drive lists as follows:
• Interface: ATA/ATAPI-5
• Formatted capacity: Up to 80 GB
• Rotational speed: 4,200 rpm
• Number of disks/drive: 2
• Number of heads: 4
• Interface transfer rate: 100 MB/sec
• Maximum media transfer rate: 297 Mbits/sec
• Average read seek time: 12 ms
• Average write seek time: 14 ms
• Latency (average ms): 5.5
Is it correct that the transfer will be similar to yours at 297 mbps (and well within 480 mbps)?

What is the significance of: Interface transfer rate: 100 MB/sec = 800 mbps?

Also, I'm not sure if you realize it, but "external" hard drives ARE internal hard drives... but with an external enclosure and a USB2.0 and/or Firewire bridge. If you already know this and you feel that I am insulting your inteligence I apologize. This is not my intention.

No offense taken. That question was not directly answerd (maybe not asked directly).


Anyhow, the efficiency of the bridge and the efficiency of the USB or Firewire controler in the computer affect how much of the drive's potential can be utilized. This could be why there aren't any charts for external drives since not only the drive used, but the bridge and the controller on the computer all become factors in how fast the drive is. Perhaps a chart of the peak bandwidth different bridges can provide would be practical, then people could match a drive to a bridge that would meet their needs.

Lastly, you can save a lot of money building your external drive yourself. You also get the flexibility of being able to choose whatever drive you want, and have the option of (relatively easily) upgrading it later. I haven't checked, but I think that USB2.0+Firewire enclosures run about $30. Add to that the price of whatever drive you want, and that's your price. Manufacturers usually charge a hefty premium for their external enclosures, and I would venture to say that in most if not all cases, building your own will be significantly cheaper.

I guess I should also mention that (assuming I got your usage right) you shouldn't need to bother with buying a FW or SATA card, making the POSSIBLE (I honestly have no idea) 132Mbps cap irrelevant.

I got the 132 mbps figure from a link in a previous post. I need to look back for bridge and controller speeds, but I imagine they must be at least as fast as the HD (?).


So firewire, USB, SATA, and other interface comparisons pertain to other devices and not really to hard drives? Why are manufacturers allowed to promote irrelevant specs about the hard drive interface? Why do interface developers soldier on to improve the interface for hard drives that will not match the interface speeds in the near future?

Hope this helped! I'll keep my eye on this thread, so post back as to whether this answered your question. :D 

Your suggestions are helpful. I am closer to deciding what to buy. The removeable, drive modules still seem to give only limited convenience, so I can probably focus on putting a drive in an enclosure, as you suggest.

I think you can get enclosures for different size (physical) drives. Are there any performance differences related to the physical drive size (reliability maybe)?

I don't believe the Gibson Research Corporation publish disc performance evaluations conducted with "Spin-Rite". Perhaps that is where Tom's Hardware charts serve the exact same function. Any thoughts as to why the true performance of hard drives is not required in product promotion?

Edit: I guess I didn't read THAT carefully... If you read my whloe post you'll realize that. Also, some laptops (mine included) have internal SATA conectors, but they're for 2.5" drives, not 3.5" desktop drives so that still wouldn't really matter.

Thank you all very much.
June 14, 2006 4:07:14 AM

So, the main thing I gleaned from your post is that your current laptop drive is a 4200RPM drive. Mine is a 5400RPM drive so it is very unlikely that your drive is faster than mine and is probably a bit slower.
Interface transfer rate is how fast the ATA bus on the drive is capable of transfering data, but has little bearing on how well the drive performs. The speed of the drive itself is the important factor. The main factor determining this is the rotational speed (RPM) and drive size (3.5", 2.5", etc) since this affects the size of the data platters and thus the the linear velocity at a given RPM.
As for the 297Mb/s (37.125MB/s) transfer rate, that is a theoretical maximum, and should be taken with a grain of salt. The specs for my drive indicate a 48.25MB/s theoretical max, but in benchmarking it maxes out at about 35MB/s.
Also, the 480Mb/s for USB 2.0 (or the 400Mb/s for Firewire) is also a theoretical maximum. In my experience USB2.0 maxes at under 300Mb/s and Firewire under 350Mb/s. In any case you have the right general idea, the max transfer rate of the drive will be less than the max transfer rate of the USB2.0 or Firewire interface.
As for different size drives, I'd recommend getting a 3.5" drive for several reasons (as opposed to a 2.5" laptop drive). Main reasons being: economy, space, and speed. Due to physical constraints, 2.5" drives can hold much less data than 3.5" drives. Also due to their size, 2.5" drives are more expenive than 3.5" drives of the same size. 2.5" drives are also slower than 3.5" drives (this can make a difference when running files off of the external drive if its faster than the internal one).
However, if portability is a factor, 3.5" drives are also quite a bit heavier than their 2.5" counterparts and are reasonably more bulky as well.

My advice, unless portability is important, get a 3.5" drive in a USB enclosure. You'll be able to get a larger drive than you could with a 2.5" drive, it'll be cheaper than a 2.5" drive of the same size (assuming its a size you can even get a 2.5" in), and it will be faster than a 2.5" drive.

I'll come up with a quick example using some info from the Toms HD Chart. Say you went with a Seagate 7200.7 drive... a bit old, but still not bad... its still a 7200RPM 3.5" drive. The 120GB version averages 44MB/s so other sizes should at least be in the same ballpark. You could either get an 80GB for $54 or a 200GB for $90. If you were to get a 5400RPM 2.5" drive (similar to the ones in either of our laptops) an 80GB would run about $100 and a 120GB would run about $140.
Now for a couple of associated warnings: I didn't comparison shop these hard drives to try to find the best deal for a particular capacity, but these prices are probably representative of what you'll find online. Also, if you're building your own external drive, make sure to get a hard drive that is NOT SATA unless you've found a SATA enclosure (in my experience they're all PATA aka ATA 100, Ultra ATA, etc) Recently SATA drives have taken off and in many cases you may find that the SATA version of a drive is cheaper than its PATA counterpart... be careful.

This turned out longer than I expected...
Good Luck! If you still have questions just keep posting and I'll get back to you when I can.

-mcg
June 14, 2006 6:30:19 AM

Why do you need to know external hd drives are limited by their USB connection. So even a 5200 RPM HD will surfice! The ones that use e SATA are usually the type that you have to buy the case then buy the HD. And in this case you can look up the specs of your HD.....

Stay away from those cheap nasty maxtor one touch with the 1 year warrinty.
June 14, 2006 11:13:55 PM

Quote:
Why do you need to know external hd drives are limited by their USB connection. So even a 5200 RPM HD will surfice!


The discussion with mcg indicates that a 5400 rpm drive will limit the transfer well below USB2. Let me know if this is not the case. I was coming to the conclusion that I could buy a USB2 enclosure and drive and get the same transfer performance as the existing internal drive (eSATA would only improve the transfer with some other hard drive).

The ones that use e SATA are usually the type that you have to buy the case then buy the HD. And in this case you can look up the specs of your HD.....

Stay away from those cheap nasty maxtor one touch with the 1 year warrinty.
June 16, 2006 8:03:06 PM

There are still some conflicting messages about the drive speed vs the interface being the limiting factors for data transfer. I think it probably is the slower speed of the two drives (limit factor).

Does it make sense to buy the best available drive (not minding the slower native drive), as the data may later be used direct from the new drive, and the new drive will probably be connected to other systems too? Similarly, would SATA or eSATA connectivity be desireable to insure that data transfer performance with other drives (in the future) is not limited by the interface?

And again, why can manufacturers promote interface speeds that are unattainable in actual data transfer?
June 18, 2006 10:38:14 PM

Its been a while and I apologize, just got done with school for the year and moved. If you are transfering files from your laptop to the external drive, the laptop's drive will definately be the limiting factor. That in mind, 7200RPM drives are very affordable so you probably couldn't go wrong by buying a drive that is *too fast* (if there is such a thing). As I (and you) mentioned, when accessing data from the (faster) external drive, it will be faster than when accessing from the laptop drive, but in this case it will probably be the interface limiting the speed and not the external drive itself

Manufacturers make a big deal about interface speeds because they are BIG numbers. Most people know little about computers and will buy whatever product has the biggest numbers associated with it. Even if they don't mean anything in a practical sense, the average consumer does not know this. Essentially it helps sell products (hard drives, processors, monitors, etc).
A good example for this is the Pentium 4 processor. When it was first released at about 1.5GHz it really wasn't any faster than a 1GHz Athlon or Pentium III, but since it was a 1.5GHz chip, people just HAD to have them... even though they cost quite a bit more. Likewise, since AMD chips run at a lower clock speed, AMD makes up speed ratings (Athlon64 3200, etc) because seeing a 2.0GHz chip would turn many consumers off since Intel chips haven't been that *slow* for ages.

-mcg
!