Hello,
The PCI-5102 is a high-speed digitizer card that has a slightly different architecture than the DAQ cards and was not built with the ability to stream data to the PC. However if you are sampling at low rates you can still acquire up to 16 million samples, which is done by using dma to tranfer data from the onboard memory on the 5102 to the PC memory. However, you will not be able to save the data to disk until the acquisition is complete.
Another option would be to purchase either a DAQ card or a PCI-5112. Both boards can continuously stream data to the host PC and you should not run into any PCI bus limitations if you are stream to disk at relativiely slower rates.