It also depends which zaurus you have!
The 5500 writes a 30mb file in about 2 mins AFAICR.
movie playback suffers, and so does doom if the wads are on sd.
32x cards go no faster at all!
On the cxx0 devices the same 30mb file writes in about 20-]30 seconds,
on the same lexar card. the 32x lexar card appears to be not much faster than the standard lexar card on the cxx0 devices.
I did start a thread on devnet where people tested the speeds of various cards on various machines.
Basically cf is faster than sd on all models, on the 5500 sd speed seems to be constrained by the bus, faster cards do not go any faster.
The cxx0 models (and I think the 5600 too) can support faster sd speeds, but cf is still faster on these models, but movie playback seems to be ok.
Peter.