Hi,
The max sampling rate that can be achieved using the single sample mode of the USB-6008 is 10 kS/s.
I'm sending to you a link that list the maximum sampling rate for this board:
http://digital.ni.com/public.nsf/allkb/6D8B3893EADBA0B786256FA5007902B5?OpenDocument
Let me know if you have any question.
Regards
Luciano Borges
National Instruments Brazil
Luciano Borges
Test Development Engineer