eSATA enclosures

Hi, I want to get an external hdd enclosure for my 3.5" WD 120gb SATA 150 Hdd to use it with a laptop. I hear eSATA is the way to go. Does anyone here have one? How do they work? Do you need an adapter or some card for the eSATA plug?

 

Hello,

There is only one problem with eSATA, you must have eSATA port on your laptop which I doubt thay any laptop have. Since there is no eSATA port, your choice will be USB or Firewire.

To read more about eSATA.

http://www.sata-io.org/esata.asp

JC

 

Popec, if you have an ExpressCard slot you can buy an eSata adapter for it for ~$60 US. This will allow you to connect the external eSata HDD normally. But USB/Firewire does fine for normal usage, and is a lot cheaper.

 

Hope you don't mind that I jump in on this.
Here's my question, related to this topic.
I am also interested in getting the fastest data transfers between my notebook and an external hard drive.
My notebook has an internal hardrive 4600RPM with 100 MB/sec transfer rate. Is a bottleneck? I'm looking at two external hard drives: one with 150 MB/sec transfer rate, and one with 300 MB/sec transfer rate- both of whic have the same internal hard drive, just different external interfaces.
Would both hard drives take essentially the same time to back up my laptop, limitted by my hard drive's transfer rate?

My other available ports are USB 2.0 and Firewire 400.
Thanks for your input

 

Hello and welcome.

I think you are referring to 4,200 RPM, not 4,600 RPM because there is no such thing. Anyway, yes 4,200 RPM is slow, compare today's 5,400 RPM or 7,200 RPM. Also cache level could affective the performance of the HD as well, 8 MB is recommendation.

If you are getting an external HD, I would go with Firewire.

JC

 

Well you could buy a PCMCIA eSAta Card. They do look very attractive. I found a link here:

http://www.cooldrives.com/saii2pecapcc.html

 

You can connect the eSATA by Firewire or USB but the speed of those devices don't go over 50 MB/sec. Theoretically, if you connect it to an Express card slot, it could run at the normal speed of a HD, ~300 MB/sec.

 

Something worth considering... The super high speeds quoted in this thread refer to the maximum bandwidth of the controller, not the physical drive. Sustained physical transfer speeds, that is from drive to controller, rarely exceed 75MB/s for 7200RPM 3.5" drives.

One definite advantage of eSATA is reduced CPU utilization which is important for video capture and the like. As has been pointed out already, for most general work, Firewire and USB work well enough.

 

um the internal 2.5 inch sata 5400 rpm drive internal in my laptop is going at 115 mb/s

according to hdtach.

My external hd on firewire which is a ide 5400 rpm 2.5 inch drive goes over 80 mb/s according to hd tach.

on usb 2.0 it goes around 40 mb/s

 

Hrm, that seems a bit off for your FW and USB readings. It sounds like it's just reading burst speeds. There is no way a 5400 rpm drive can have a sustainable transfer of 115 mb/s. Unless it was reading in series, but random read/write, akin to normal operations would be no where near that. Even 7200 rpm 3.5" hdd don't often hit any where near that high, unless in raid.

 

I'm guessing that Stamar is either referring to burst transfer speeds, in which case you're talking about data that's sitting in the cache, or more likely an aversion to using the shift key is causing us to confuse MB (Megabytes) with Mb (Megabits).

Considering that Stamar has quoted a speed of 80 mb/s for his external firewire drive, which exceeds the total bandwidth available on Firewire 400 (assuming 10 bits per byte including protocol overhead), I'm guessing the latter.

Remember, there's an order of magnitude difference between Mb and MB.

:EDIT: Just looked at HdTach (never used it)... all figures are in MB, so you're quoting burst speeds. Sequential speed is more important for high volume R/W operations.

 

ok actually I have an update

the burst speed was 115 to 119 for both the sata internal and the firewire external to ide both 2.5 inch 5400 rpm
( it is firewire 400)

the average read time is 33.3 MB/s

It says the sata interface is 150 MB/S so the burst speed approaches the sata interface.


for the same external drive in usb 2 the burst speed was 33.3 MB/s but the average read was 26 mb/s
Although it is supposedly similar average read speed according to hd tach, the usb connection is way slower I get the feeling like 4 times slower.


all mbs mean megabytes here.
ill do the firewire one again if youre interested.

The only reason im doing this test is because Im going to get another 2.5 inch external case for the hitachi 100 gb. According to my test it wouldnt benefit from esata at all. firewire ( and usb 2.0) seem to be faster than it can go.

Ok so I am not going to look at the burst rate then just the sequential read. It goes 33 mb in internal sata, dif drive same speed goes 26 mb in usb 2.0 and 33 mb in firewire 400

 

Yah, those numbers look better. But keep in mind it's artificially inflating those numbers because it's using 1 MB = 1000 KB instead of the actual 1 MB = 1024 KB. Not that is makes a huge difference though.
I just get annoyed when software does that.

With esata, I believe another benefit is that there is lower overhead than with USB and FW. That should help some.

 

yes there is a stat that shows 2% cpu utilization with internal sata

but 18% with external usb 2.0

I dont remember what the external firewire was at all. Im going to redo the test tonight and look.

Im not sure what that stat really means. However, if it means sometihng 16% difference in cpu utilization is big.

I want to see firewire though. Im not actually comparing usb 2.0 to esata for my purpose, im comparing esata to firewire.

 

The problem with USB2 drives is there are an awful lot of host and device chipsets, many of which don't work terribly well with each other... so your burst/sequential speeds will vary (wildly) depending on the chipsets used. Trust me on this, the 26 MB/s average you're getting is not the worst I've seen by a long shot.

Firewire is a better proposition because there are fewer host/device chipsets out there, and most of them are well implemented. The result is better throughput speeds and lower CPU utilisation.

As I mentioned in my initial post, eSATA is great because it offers guaranteed high throughput with minimal CPU utilisation, making it perfect for real-time video capture. For general use, it's probably overkill.

:EDIT: This mini review (performed under OS X) of an early eSATA adaptor is quite informative.

 

and this is the same drive as test 2, same enclosure but using the firewire.

It has almost the same burst speed and seq read time as the internal sata

it says it uses 4% cpu utilization as opposed to 2%.

Virtually identical to the internal hd even though it is ide through firewire. It is actually faster by a little...

I did a lot of driver updating to get this speed btw.

 

Thanks to all of you for weighing in on this discussion.
I would like to explain a little more about what I'd like to use this drive for. I am a scientist who often works with large data files. These files have consumed much of my hard drive.
I have another off-site back-up, but would like to have an external hard drive so I can keep all of these large files off of my main internal drive. Since my hard drive is relatively slow- I benchmarked my an average read time of 32.4 MB/s with a burst of 92.8 MB/s- I was wondering if I moved these data files so I accessed them from an external HD using eSATA or firewire 400 , if I would experience some sort of latency inherent to accessing the files on an external HD (oppose to accessing them from an internal HD).
Or, since I would be running a program on my internal drive that I would use to analyze the data files on the external HD, would I still be limited by the internal drive.
Again, thanks for the input. My main concern is whether I should by an external drive case with firewire or if I should by an eSATA PCMCIA card and a eSATA case.

 

I have an Vantec NexStar3 case that bought for $30 on Newegg. It has an eSATA and USB connection on it, so you can use it either way. I also have a eSATA express card adapter I bought for $35 on Newegg. It's worth it. I've installed all my games on my external hd and I've noticed an increase in performance with my games, since my external hd is faster than my internal.