storing the hash multiplier instead of the hash value

[Walter Bright]

Andrei Alexandrescu wrote:
> As we discussed, if nodes are allocated in bunches, you could store 5 
> nodes in a 64-byte block instead of 4. That's more than a 25% increase 
> in effectiveness because the per-block bookkeeping is also slashed by 5.

Right, but the downside is that the nodes will not be collected unless all its 
neighbors are also not used.