Archived from groups: microsoft.public.windowsxp.hardware (
More info?)
Nathan, Many Thanks for the detailed response. It totaly answers my question.
BTW your guess about what I want the card for is very true; I am planning to use it with an external ATA133 HD.
McMakan
"Nathan McNulty" wrote:
> Goo, I am stupid. Got MB/s and Mb/s mixed up. Ok, so let me fix this:
>
> USB 2.0 has a max throughput of 480 Megabits per second, this is 60
> Megabytes of data per second.
>
> The cardbus has a max throughput of 850 Megabits per second, this is 132
> Megabytes of data per second.
>
> So the cardbus will actually only use about 55% of its available
> bandwidth for the USB 2.0 Card and will fully support the maximum
> speeds. Oh, and I fogot to mention my sources:
>
>
http://www.pcmcia.org/papers/new_bus.htm#usbde
>
> Nathan McNulty
>
> Nathan McNulty wrote:
>
> > The theoretical limit to 32bit cardbus is 132 MB/s. Now you are only
> > going to get about 80% efficiency, so you are only going to really get
> > about 105 MB/s. This is still much better than 12 MB/s (which really
> > ends up around 8 MB/s. Here is the deal though. Current harddrives
> > today can only handle around 78 MB/s internally. When you have
> > ATA100/ATA133, these speeds are only achieveable by RAID configurations.
> > This is the only time when you can actually use max throughput. So
> > basically, get a USB 2.0 PC-Card. It will help you a ton and the only
> > way you are going to not reach full speed of the USB is if you copy
> > large files to two different harddrives (in your laptop? lol) at the
> > same time. Basically each harddrive will accept around 80 MB/s. So USB
> > 2.0 could fuel multiple harddrives even if they were SATA set up in RAID
> > Configuration
> >
> > Nathan McNulty
> >
> > McMakan wrote:
> >
> >> I am about to buy a USB 2.0 PC-CARD for my P-4 laptop running XP. But
> >> doing a bit of search, I am acutally confused if the 32-bit carbus on
> >> my laptop is fast enough to allow the use of the full USB 2 speeds of
> >> 480 Mega Bit Per Sec (the most I could find out was that the speed of
> >> a 32-bit cardbus is just 50 MBPS!!?
> >>
> >> I don't want to end up with yet another useless bit of hardware
> >> gathering dust in the attic, so if you know of anything that might be
> >> useful for the above quesiton, your help is much appreciated.
>
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