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Re: PCI bus speed on OldWorld PCI macs

Although I don¹t know actual numbers on the hardware side of things I can
give a few bits of real world info on this...

Here at home I have a B&W G3-500 (384megs RAM OS X 10.1.5) and a 8500/233
(604e) ( 896Megs Ram Mac OS 9.1) with a KNE110TX 10/100 enet card... And
when the B&W is hooked to my friends iBook it will blow large files back and
forth very fast... But when I have the B&W G3 and the 8500 hooked together
it is hardly noticeable speed increase from the built-in 10T connection...

At work we have a Starmax 3000 (basically a 4400 with a different riser
card) with a 300Mhz G3 as a file server with a RTL 8139 in it... And when
serving to the machines with 100TX it is not much quicker then 10BT but the
machines with 100TX go very fast between themselves... note: the Starmax is
running Debian 2.2r4 and all the other machines on the network are Windows
98SE machines (yes I like the irony of a Mac running Linux being a
fileserver for a bunch of pc's they converted from all Macs to pc's and the
only machine left to be a file server was a Mac... :')


on 8/2/02 2:11 AM using moldy cheese mlan@cpu.lu engraved this message

> On   1 Aug, this message from Michael Hackett echoed through cyberspace:
>> On Thu, 1 Aug 2002 16:50:41 -0400 (EDT)
>> "Albert D. Cahalan" <acahalan@cs.uml.edu> wrote:
>>> Michael Hackett writes:
>>>> No, because you can't change the PCI clock.
>>> Do you know this specifically for his hardware? Remember that
>>> it is 100% allowed to run PCI at less than 33 MHz, and that
>>> this is common.
>> Ah, well, I've never heard of that on the Mac side, but that may be the
>> case. From everything I've read, the PCI clock was independent of the
>> system bus clock, but nothing's to say that information wasn't wrong.
> No, you're right. The PCI clock is fixed at 33 MHz.
>> Can you point me to a source for more info?
> Look for this here on Apple's developer site:
> Designing_PCI_Cards_Drivers.pdf
> Also, Apple technote 1008 is of interest.
>> Regardless, the fact remains that any PPC Mac has plenty of PCI
>> bandwidth for megabit Ethernet.
> Well, I'm having problems with a 100Mb/s Ethernet on my 7600. Remember
> that 80 MB/s is the absolute maximum according to Apple
> _under_optimal_conditions... meaning using 'Read Multiple' and 'Memory
> Write & Invalidate' PCI commands for the card's DMA operations. No idea
> what the RTL8139 on my card really uses....
> Cheers
> Michel
> -------------------------------------------------------------------------
> Michel Lanners                 |  " Read Philosophy.  Study Art.
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