[throw0101a]

> My understanding is that implementing a PRNG in software results in a very small entropy pool.

A lot of PRNG are now implemented as the output of stream ciphers or block cipher in counter mode:

* https://en.wikipedia.org/wiki/Fortuna_(PRNG)

So 128 bits is all that is needed to get going.

Re-key every so often to ensure forward security in case there is a kernel-level compromise.

With AES-NI instructions in most CPUs, several GB/s can be achieved.