It takes a long time to open a PDF file when there is a smart card attached to the computer. This issue can occur regardless of whether the smart card is used in Acrobat/Reader.
Update to Acrobat 9.4.5, 10.1, or later.
When the smart card is attached to the computer, Acrobat detects there is a certificate available. It tries to validate the smart card by checking the certificate chain in the Acrobat and the Windows trust stores. There is a known issue in Acrobat where the algorithm performing this certificate check is inefficient and loops through the chain multiple times. Adobe has improved the performance of the certificate check. However, it has no influence over the other components that lead to the total delay where a smart card is inserted. There are also known delays in smart cards, the reading device and driver, and in the Windows trust store.