FWIW, I have tried a CF-IDE adapter in my Performa 630CD and none of my CF cards worked (although the adapter and cards worked in other machines and with SCSI-IDE converter + CF-IDE adapter). That doesn't mean it *won't* work, just the cards and/or configuration I used did not work with it.
I tried Kingston 133x 8GB and a SanDisk UltraII 4GB card.