Wait, how did CardBus get invoked here? The CompactFlash adapter the OP is using (pictured in the OP) is plain PCMCIA, and CompactFlash cards themselves are a subset of 16-bit PCMCIA/ATA. As was noted, the "mod" to let a Cardbus card work in the 3400 is just hacking some plastic away, that's not going to change the power supplied to an inserted card in any way.
(There *are* Cardbus-based CF adapters; honestly not sure what the point is since the speed is going to be limited by the CF interface, but one would be identifiable by the gold ground-plane on the upper surface of the plug.)