Mailinglist Archive: opensuse (1556 mails)

["Brian K. White" <brian@xxxxxxxxx>]

Tejas Guruswamy wrote:
> On 03/02/10 09:52, Sampsa Riikonen wrote:
> > What seems to be the problem?  Am I missing something in the math?
> > My external usb hard disk box has also an option to use an esata connector
> > (but then I should buy an adaptor to my laptop), but the speed difference
> > to usb 2.0 is not that big, I imagine..?
> >   
> ESATA has a capacity of 3Gbits/sec vs USB2.0's 480Mbits/sec. In fact
> with ESATA the choke point is usually the read speed of the drive, not
> the bus speed. The disadvantage is that your computer must have a ESATA
> port (desktops can fit an expansion card into a PCI-Express slot, but
> it's difficult on laptops) and also ESATA doesn't carry power.
>
> Tom's Hardware recently had an article[1] comparing the speeds of
> USB2.0, Firewire800, and ESATA and found a clear difference. For
> instance using a 1TB Hitachi G-Drive they were getting 100MBytes/sec
> read speeds on ESATA vs 35MBytes/sec on USB2.0.
>
> After saying all this though, USB3.0 at 4.8Gbits/sec will be introduced
> over the next few years.
>
> Regards,
> Tejas
>
> [1] http://www.tomshardware.co.uk/usb-firewire-esata,review-31793-8.html

You are also forgetting that different ports consume different amounts 
of cpu.

A 400mbit firewire port can be faster than a 480mbit usb2.0 port because 
the firewire uses a lot less cpu than the usb.

There are also differences in motherboard design. Usb ports and (e)sata 
ports (nor gigabit lan, nor anything else that's built-in) aren't all 
the same. Some are implemented very well and some are implemented very 
cheaply.

I would expect an esata port to be pretty efficient compared to a usb 
port on the same motherboard in pretty much all cases, cheap or good, 
but it's not an automatic given just because it says esata on the side.
And the less efficient usb port on a good motherboard could be faster 
than the more efficient esata port on a cheap motherboard.

--
bkw
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