To improve the performance of large bulk copy operations, you may want to use larger network packet sizes than the defaults. The -A size option specifies the network packet size to use for the bcp session that you are beginning.
The value of size must be:
Between the values of the default network packet size and max network packet size configuration parameters, and
A multiple of 512.
The new packet size remains in effect for the current bcp session only.
For example, this command specifies that Adaptive Server send 40K of text or image data using a packet size of 2048 bytes for the bcp session:
bcp pubs2..authors out -A 2048 -T40960