How much does a USB decrease the speed of my hdd?

[AznKwaiJai]

The max size of the external can hold a 350pata hdd. Just wondering how much does the usb actually slow down the speed of the hdd. I don't want to buy a hdd that is faster than what the usb can transfer. http://www.newegg.com/Product/Product.asp?Item=N82E16817146307

 

[Mark R]

USB can transfer about 20 - 25 MB per second from an external hard drive.

All hard drives, of that size, on the market today have transfer rates way faster than USB.

That said, if you are working with lots of small files (instead of a few huge ones, e.g. movies) then the lower access times of a 7200 rpm drive may be noticably better (even on USB) than a 5400 rpm drive.

 

[AznKwaiJai]

Okay thanks.

 

[Zepper]

For external HDDs you can get a bit better performance from Firewire even though the spec shows a lower transfer rate than USB 2. (400 vs 480 Mbits/sec) eSATA can do better and Vantec (maybe others too as I don't think Vantec actually makes anything they sell - just a packager) has a PCI eSATA card now that isn't too expensive.

.bh.

 

[eelw]

Text

Here's a benchmark comparison between a 250GB WD IDE drive and used in an enclosure with Firewire and USB.

 

[Peter]

... confirming what one generally may expect - roundabout 25 MB/s on USB2 and 35 on FireWire-400. FW-800 aka IEEE1394b will give that a nice boost. The first enclosures are appearing on the shelves just right now.

 

[Zepper]

Wouldn't eSATA be the best idea for extermal HDDs now - even over FW800, since you'd be starting from scratch in either case (needing both a new PCI card and enclosure for either). Nothing else I know of needs a faster interface.

Of course there's always external SCSI which has been around for years, but generally not intended for routine unplugging...

.bh.

 

[Peter]

eSATA sure would be nice for a single drive.

FW in turn gives you daisy-chaining, connectivity to non-disk stuff like scanners and cameras, and peer-to-peer operation, e.g. direct copy from camera to harddisk without involving a host PC.

 

[corkyg]

eSATA would be great for an external drive - but I have yet to find a laptop that has such a port, even thought the internal drive is SATA. One would think such an external port would be easy in that case. ???

 

[Peter]

eSATA would be rather trivial to do from a Cardbus or ExpressCard slot.

 

[postmortemIA]

yay that sounds like i can have laptop with external Raptor drive

 

[Peter]

As long as you remember that 3.5" drives do NOT AT ALL like to be bumped around in bags and suitcases.