To Tracer bullet and all other 4 PCI Slotters: H ere is the email I just received from one of my gurus's:
You can't use 4 PCI card with the KT7A - or any other motherboard that has
an on-board RAID controller.
The PCI specification says that there can ONLY be 4 bus-mastering PCI
devices on the bus at once.
No matter what.
The on-board RAID is a PCI device, but it doesn't take a slot.
Almost all PCI devices are bus-mastering, so you won't be able to use more
than 3 of them.
That is NOT abit's fault, but a basic design decision back in '92 when PCI
was invented.
The reason that motherboards with 5 PCI slots existed was back in the
Voodoo2 days.
The voodoo2 was a very simple device that did NOT require bus-mastering or
an irq.
Since many people had 2 voodoo2 cards, then with 5 pci slots, they could use
3 other PCI devices without a problem.
Needless to say, the people who are bitching at ABIT about this are just
ignorant as to how the basic subsystems in a computer work.
If they want to use 4 PCI cards, all they have to do is disable the onboard
TO TracerRAID controller.
This phenomenon occurs on ALL motherboards from ALL manufacturers.
The only way around it is to put a dedicated PCI arbiter chip that is
separate from the motherboard chipset (basically a 2nd PCI controller)
That will allow you 4 more bus-mastering devices, since there will be in
effect, 2 PCI buses in the system.
This is quite expensive however, and you'll only see this feature on
high-end server motherboards that NEED that many devices (like Tyan,
Supermicro, etc.)
Feel free to post this message verbatim to whoever/wherever was discussing
this issue if nobody has set them straight yet.