On 15 May 2002 01:07:11 -0400, Lyvim Xaphir <[EMAIL PROTECTED]> wrote:
> On Tue, 2002-05-14 at 23:19, Sridhar Dhanapalan wrote:
> > How is the CPU usage of USB compared to the 'legacy' ports (serial,
> > parallel, PS/2, etc.)? The legacy ports were designed for older systems, so
> > they cannot suck up too much juice.
>
> It is interesting that you bring up the CPU usage aspect of USB, as I've
> not seen any numbers regarding that. The resource benefits I was
> referring to was directed towards IRQ usage, because I have a real need
> for extra IRQ's (and I suspect others with legacy hardware do also), so
> in that regard the USB bus was a real benefit. There's a lot you can do
> with three extra IRQ's. I am interested in CPU utilization numbers, if
> you've got some URL's...
I don't have any URLs; I'm just heard/read anecdotes about this. It just may be
that USB devices do more than their PS/2 and serial versions. For instance, I
read a review on the USB optical Intellimouse a few months ago. The reviewer
said that the mouse was far more accurate and responsive in USB mode, but when
he tried to use it in Quake 3 it slowed his machine so that he couldn't play it
properly. He switched to PS/2 mode using the supplied adaptor, and the mouse
became less responsive but also less-taxing on the CPU.
> > I hear that USB, on the other hand, is a real pig in
> > this regard (no surprise that Intel supports it). If that is the case, is it
> > really worth using USB peripherals on a PC when legacy types would suffice?
>
> That begs the question of some numbers, does it not? Such as, what
> exactly is required for the device in question? (is it an isdn modem,
> or....) Not only that, but in order to answer your question properly you
> also need some performance numbers in regard to the chipset platform
> that is giving you the USB functionality. Quite naturally, this is
> going to be giving different performance results depending on which
> chipset platform you choose; i.e., Intel or Via. "Performance" in this
> context meaning both CPU utilization and USB bus throughput.
I'd love to see a performance comparison of the different buses. Does anyone on
the list know of any?
--
Sridhar Dhanapalan
"I once preached peaceful coexistence with Windows.
You may laugh at my expense -- I deserve it."
-- Jean-Louis Gass�e, founder of BeOS
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