I have the above mobo for which I recently bought an extra 256 Mb pc133 RAM.Adding to existing 64Mb pc100 and 128 Mb pc133. However, the mobo is only recognising the new RAM as 128Mb giving a total of 320 Mb instead of 448 Mb. On the mobo menu, it gives a maximum of 768 Mb. The RAM are all non-ECC unregistered. I am just wondering if there is any way of making the mobo recognise the full amount.I have flashed the BIOS to the newest available.

Most 256MB PC133 modules these days are "high density". Since your board has 3 DIMM slots with a max of 256MB per slot, you MUST use low density modules.

When installing high density RAM in a board designed for low density, one of two things will happen:

1. the system will not boot
2. the new RAM will be recognized at 50% of it's capacity

There is no way to get the other 128MB recognized. Simply put, you bought the wrong RAM. BTW, since you have a stick of PC100 in the mix, ALL your RAM is being forced to run at PC100 speed (100MHz).

"And that's the fishing line, because Sharkboy said so!"

The OP seems to be running a 112 fsb so all three sticks most likely are running at 112MHz. Try to return the memory for pc 100.

Thanks. I bought the generic RAM 256Mb for about $15 as the branded ones are $60-80.
The system appears stable and runs ok.
Read somewhere about how the generics are 64x4 while branded ones are 32x8 etc.
Guess 320 Mb will have to do.

Yes, you are right Wemby. The fsb is at 112. When I turned it up to 133, the system kept on freezing, but is running smoothly at 112. The pc100 came with the board years ago. The pc133s are newer comers.

"When I turned it up to 133, the system kept on freezing"

That's because you have that stick of PC100 mixed in with the PC133. Remove it & you *might* be able to run stably at 133MHz.

"And that's the fishing line, because Sharkboy said so!"

You are running the katmai pIII and they maxed out at 600MHz. These ran very very hot and I would not try 650MHz without a real good cooling solution. The ram would hold you back but I think your cpu is also overheating at that speed. If you really need more speed look on ebay for an upgrade, although I would probably just live with what you have.