At 15:30 -0400 06/13/2005, Quadlist wrote:
Date: Mon, 13 Jun 2005 10:02:02 -0400 (EDT)
From: Nate <[EMAIL PROTECTED]>
On Thu, 9 Jun 2005, Jeff Walther wrote:
Anybody recognize this:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4604&item=5206968963&rd=1>?
It looks like it plugs into a Quadra PDS slot, but it also appears to have a
68040 chip on board. So what would be the point?
Jeff Walther
The Quadra 700 and 900 were only 25Mhz when introduced, and the
Quad040/Image040 were 68040 PDS upgrade cards that would take the machines
to 40Mhz and could also take a daughtercard with two of the AT&T DSPs that
were used in the 660AV and 840AV. However, those DSPs were not recognized
by the OS the way there were on the 660 and 840, but they could be used
with Photoshop as filter accelerators with special plug-ins.
Later on companies like Sonnet and MicroMac developed CPU socket upgrades
that let you put a 50Mhz 68040 into a 25Mhz socket thanks to some
additional circuitry, however the bus timing issues caused some
side-effects like the floppy drive no longer working. AFAIK the
Quad/Image040 never suffered from problems like that.
Ah, thank you for satisfying my curiosity, Nate.
I didn't understand why one would put a 68040 upgrade in a Quadra,
but I guess it is difficult to see, now, how attractive such an
incremental upgrade would have been back then.
These days there's essentially no difference in price between a 25
MHz and 40 MHz 68040. Back then it could make the difference between
spending several thousand dollars on a new machine. And 25 MHz to 40
MHz is theoretically a 60% speed boost.
I'm also in the habit of thinking of the post-Q700/900 machines, most
of which have a hack available to take them to 40 MHz without adding
an upgrade.
Jeff Walther
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