[CIA]

At what point did PM's go to 64 bit PCI slots? Are all three of them 64 bit?

[Scotttheking]

At least since the B&W G3.
And yes, they are all 64bit.
The long ones are 64bit.
The B&W G3 also has 1 32bit PCI slot.

[CIA]

Does it slow things down mixing 32bit and 64bit PCI cards? Short of opening up the case is there a way to tell if a card is 32bit or 64? I have 2 PCI IDE cards, they both are new last fall. I guess they are 64 bit. I only wonder about my old PCI ATI XclaimVR 128.

[Scotttheking]

Originally posted by CIA:
Does it slow things down mixing 32bit and 64bit PCI cards? Short of opening up the case is there a way to tell if a card is 32bit or 64? I have 2 PCI IDE cards, they both are new last fall. I guess they are 64 bit. I only wonder about my old PCI ATI XclaimVR 128.

No, it doesn't slow them down.

Open the case and check the length.
A card that plugs in to the whole slot is 64bit, a card that stops about half way back is 32bit.

[D'Espice]

There are several PCI specifications and some of'em can not be mixed without slowing things down:

32-bit/33 MHz: default PCI
64-bit/33 MHz: what Apple uses, compatible to 32-bit/33 MHz
32-bit/66 MHz: some servers use that, 32-bit/33 MHz PCI-cards will slow things down
64-bit/66 MHz: some servers use that,64-bit/33 MHz and 32-bit/33-MHz PCI-cards will slow down, 32-bit/66 MHz will not.

The bottom line is: You can mix 32-bit and 64-bit PCI-cards which will not slow down things at all but as soon as you mix 33 MHz and 66 MHz all PCI-cards will only run at 33 MHz.

[angelmb]

Also the voltage of the PCI cards is different:

PCI number 1: graphics card, 66 Mhz, 32 bits and 3,3 voltios
PCI number 2,3 and 4: 33 Mhz, 32 and/or 64 bits and 5,0 or 3,3 voltios