what is the fastest sustained data rate possible? I am looking into a 4GB 80x cf card, wanna make sure that the supporting hardware can "use" the speed. Yes I am going to replace the microdrive for this "alternative". Perhaps a 8GB if the bus/controller cant handle 80x.

Short answer: you may or may not see a speed increse

Long answer: Boot time are cut, and you will get longer battery life

the CF bus on these devices is also attached to the RAM in your system so getting a file from the harddrive impacts the entire systems performance (RAM is 100Mhz * 4 byte a sec max transfer rate, whereas CF maes out at 16MB/s (the newer CF+ 3 spec tops out at 66MB/s and supports DMA

shrt bursts should see a speed improvment however i have never seen one of these cards reach the rated speed, the details are hidden away in the data sheets which say that not only is it a theretical max but that it only occurs under certin conditions (ie reading/writeing huge amounts of data at a time

the 8G card would also have a larger cache which would boost performance when dealing with files whos total combined size is less than cache, however this cache helps with overall bus speed if you have read ahead on and at a good value as it prevents the bus from thrashing (which is very bad)

i doubt you would notice a diffrence

IMHO i would stay with the micro drive for swap but if you dont use that then you are better off with the flash card

so the z would find a use for the new 80x cards....

i would say yes but wether or not you would notic it is a difrent matter, if you have the cash i would not hesitate as it comes in handy for other things

I think 1 Mbyte/s is the best you can get form a CF slot regardless of the speed of the CF card itself

even the internal slot in the 3100?

there is no diffrence between the external and the internal slot apart from a peice of plastic note if you copy to/from the internal slot to the external then you halve the transfer speed