For those who are trying out the DB version on HDD (not SSD), I've made a small tweak to the code that massively improves HDD performance.
On bitmonero/src/cryptonote_core/BlockchainDB_impl/db_lmdb.cpp, change line 727 from:
if (auto result = mdb_env_open(m_env, filename.c_str(), 0, 0664))
to:
if (auto result = mdb_env_open(m_env, filename.c_str(), MDB_MAPASYNC | MDB_WRITEMAP, 0664))
I'm not sure whether it may have some implications like corrupted data on crash or something, but I've tested killing the daemon while syncing, and starting it up again, and it continued without any trouble from where it left before killing it.
The only side-effect I've noticed so far, is that it instantly allocates 16GB to data.mdb, but it makes it incredibly faster.
So, if you want to try it out, do it at your own risk
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
Cheers!