Fastest way to read data out from AD board?

Hi all
I have a PCI-DAS4020/12 which I have been trying to use in a air  
warning radar system. What will the fastest way to read data from the  
card. At the moment I am using the read interface as shown in the  
cmd.c program, but I wonder if some other mean of reading data out  
would be faster, maybe mmap or some other comedi software interface I  
have not found yet.

I am sampling at 1 MHz and have new data around at a speed of 400 Hz  
and I need to take as much data as possible and do some pre-analyzis  
on the data on the same machine, so I really need the maximum  
transfer speed in this application.

Best regards Assar westman