Using a bootstrap.dat is no longer recommended (Unless it's an old coin).
Viacoin uses a new faster-synchronization feature.

‘headers-first synchronization’: The Viacoin Core Beta wallet first ask peers for block headers & validate those.
In the second stage, when the headers have been discovered, the Viacoin wallet downloads the blocks.
However, the wallet already know about the whole chain in advance, the blocks can be downloaded in parallel from all available peers.