You can't build an UTXO set (needed for validation) without doing most of the verification anyway (everything except signature checking, basically).
"most of the verification anyway" ... I like to weight this "most" by real-time not by code size or "logical" verification-classes and then it turns out that the signature checking needs 99% or far more of it (depends on your disk speed).I sure, I fully agree. In terms of CPU usage, signatures validation outweighs everything. But before the last checkpoint (=exactly what is stored in bootstrap.dat), signature checking is disabled anyway (and this hasn't changed in 0.
.Also, I assume that importing bootstrap.dat on your hardware will take more than 5 minutes. Done completely in RAM, it's probably possible, but the client also maintains a database on disk, and does synchronous writes at times to make sure block data and index/coins remain consistent with eachother.