Quick question on 64bit, 66mhz PCI slots...

[Insane3D]

I'm considering setting up a dual Tbird setup based on a 761MPX chipset. I'm leaning toward the Asus A7M266-D, and I had a question regarding the 64bit PCI slots. According to Asus from their A7M266-D Specs page, they say the following..

"Two PCI 64-bit 66-MHz slots deliver up to four times more bandwidth than conventional 32-bit PCI slots, and are optimized for server or workstation functions. 64-bit PCI slots are backwards compatible and also support 32-bit PCI cards or peripherals.

So, I'm thinking I can use the 64bit PCI slots if I need to with regular 32bit PCI cards, but I then look at the picture of the slots on the board and it looks like they are reversed. How does a 32bit PCI card fit in those?

 

[Lord Evermore]

64 bit 66MHz 3.3volt slots are compatible with 3.3volt 32bit PCI cards only.

Many PCI devices are 5 volt only, which is the "reverse" slot compared to the 64bit slots that you've noticed. However many devices are designed to function in either 5 volt or 3.3 volt slots (consumer motherboards come with 5 volt slots, as all consumer devices will be compatible at least with that; if they only had 3.3 volt slots, there'd be many devices that couldn't be used in that slot).

64 bit, 33MHz, 5 volt slots can accept 5 volt 32 bit PCI cards.

Technically, Asus isn't lying, they're just not being totally truthful. When buying PCI devices for that board, you'll have to be sure that you buy 3.3volt compatible devices.

 

[Insane3D]

Ahhh..so that's what my Netgear NIC means by "Use it in future 3.3-volt PCI systems, and in 5-volt PCI systems". Thanks for the explanation. That just about covers it..thanks!

Now all I have to do is decide on the Asus or wait for the Epox...

 

[Lord Evermore]

I'm not sure I like the description on the Tyan website, about the MPX requiring use of some main memory to allocate to PCI devices, and the more devices, the more memory it takes. Up to HALF A GIG used for that on the Tyan MPX! I've no idea if that's common on multiprocessor boards, or certain designs, but I've never heard of it before.