I asked Western Digital this exact question. This should not be a problem
but read the documentation to your add in ULTRA controller or your
motherboard...on Board ULTRA Controller. I use a FIC PA 2007 which clearly
states that I can use different modes on the same channel sharing the same
cable with no loss of performance. Modern controllers are intelligent
enough to make the distinction.

Mark
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At 03:10 PM 4/26/98 +0000, you wrote:
>Bought a 6 gb UDMA Western Digital, and was thinking of keeping the
>non-UDMA as a secondary.  Will there be a problem with the vast
>transfer rate difference between the two drives?