>> > I have 2 64-Bit PCI slots on my board. Some 32-Bit cards fit in them
>> > (the ones with the front notch), but others do not. What's the deal?
>> > What does the front notch signify? Does that mean that the card that
>> > fits is able to run at the 66Mhz speed or something?
>> If you mean the one close to the metal clamp it indicates
>> a 3.3V Bus. Some cards have both notches, which means they
>> support 5V and 3.3V operation.
>> You might get away with cutting a notch to make a card fit
>> mechanically. It might even work. But you are asking for
>> trouble. It will fail when it can do the biggest damage :^)
>I fulle agree! Don't do it, Dan! Here is a picture, for everyone's
>The one slot that is not shown there is a 3.3V, 32-bit one - fairly
>rare. That one has the rib on the left (in the picture) side. BTW, the
>left in this picture is the back adge of the mobo, where You connect all
>Your stuff to the cards.
> And yes, some 32-bit cards have both notches and adjust to the slot
>voltage. Haven't seen a 64-bit card like that, yet - but then again, 5V,
>64-bit PCI is not very popular.
Also note that 66 MHz operation is always with V[IO] at 3.3 V (not
100% sure for desktop PCI, but it is for sure in the specifications for
CompactPCI). That is (almost certainly) why no 64-bit 66 MHz PCI slot with
5.5 V V[IO] is shown. 64-bit 66 MHz PCI devices might be able to tolerate
5.5 V V[IO], but the specification only allows for them to do this at 33 MHz.
For your reference: I fried an old (and probably expensive at one
time) 5.5 V V[IO] 3U CompactPCI backplane video card by putting it in a
backplane with V[IO] wired for 3.3 V. No smoke came out, but it mysteriously
did not work any more. (This happened in the course of testing hardware
produced where I work for 3.3 V V[IO] compatibility -- I knew which of our
stuff to avoid, but this card was made by another vendor and had no
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