On 11/16/11 10:41 AM, Brielle Bruns wrote:
No. The long slots in a G4 are NOT PCI-X. The original PCI slot spec
allows for a long version that requires the extra slot length.
Uh, I think your confusing full length cards and regular length cards.
Both of which could be PCI or PCI-X. Card length is not the same as slot
length.
The G4 has PCI-X slots - I have a MDD sitting here, next to me, with a
PCI-X fibre channel card running in 64bit, albeit its the older PCI-X
standard so it only runs 33mhz.
Just confirmed this with Mactracker - there's 4 PCI-X 64bit/33mhz slots.
For future reference, handy chart helping you figure out what kind of
PCI slot you are looking at:
http://en.wikipedia.org/wiki/File:PCI_Keying.png
Some background on PCI-X, it was created before PCIe came into
existence, as a way of giving servers and high end desktops the ability
to use more high bandwidth needing devices such as fibrechannel cards.
By default, PCI runs at 32bit/33mhz, which doesn't really have the
bandwidth necessary to support the kind of performance the card is
capable of.
The extra slot length adds more bus pins - specifically the ability for
the card to activate 64bit mode and the extra pins needed to do those
transfers.
Provided the card supports 32bit operation (which most do, albeit much
slower speeds), you can take a PCI-X card and put it in a PCI slot and
it will work.
PCI-X also added the ability to clock the cards higher then 33mhz - both
on 32bit and 64bit cards. Towards the mid to end of PCI's lifetime,
regular PCI slots could have the ability to do 66mhz and higher provided
the chipset supported it.
Picture of a G4 MDD showing the PCI-X slots on the left hand side:
http://guide-images.ifixit.net/igi/YU2gIgVCdH1L3hSa
I believe the Quicksilver motherboards has PCI-X as well:
http://www.recycledgoods.com/product_images/u/653/s_p_22951_1__73791_zoom.jpg
--
Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org / http://www.ahbl.org
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