kt133 and kt133a

Does anyone know what the changes were between these two chipsets specifically?
I have the kt133 non-a and I've been trying to get my fsb higher for memory bandwidth. I've got it to post at 130fsb, I had the hd disconnected cuz of the high pci freq. Any higher and it doesn't boot. I've read everywhere about how this chipset doesn't like to go about 110-115fsb but I want to know why.

Any ideas?

It's because it doesnt have a 1/4 divisor so;

115 / 3 = 38MHz PCI BUS
130 / 3 = 43MHz PCI BUS

The SB can not function at those speeds so the newer KT133A has the KT133A NB, which recognizes the 1/4 divisor from the clock generator, & the 686B SB, which is also more tolerant of high bus speeds, to replace it but you probably know that already.

Thats what i was guessing.. but no where actually states thats what the problem was.. in the bios is says the pci bus switches to 34 at 135 but i suspected it wasn't switching.

Thanx for the info

[xeno]

The difference between the KT133A and non-a is the FSB it supports. The a version supports 133 FSB sppeds while the non-A only supports 100 FSB. It sounds like the non-A has a 1/4 divisor, but you'll probably never get the board to 133 FSB where the 1/4 divisor would be used,

Aaron

The KT133 is not as good as the KT133A basically. As per VIAs usual process of releasing a chipset asap (aka KT133, KT266) they often release an A version later (KT133A, KT266A). I imagine the KT133A will also fix any bugs in KT133 as well as allowing a higher FSBs.

KT133 isnt viable for any new PC at all, and only useful for Durons or Tbird-Bs.