From Genome Analysis Wiki
* '''Improved Speed - ''' Minimac4 is approximately '''6 times''' faster for 1000 Genomes Phase 1 and Phase 3 and '''2 times''' faster for the HRC reference panels at comparable accuracy (details of accuracy for imputing into 10 European samples are given here). The speed can be further improved by tuning the approximation parameters (see below), but we recommend using the default values.
* '''Automated Chunking - ''' Minimac4 automatically chunks the whole chromosome (into overlapping chunks), analyzes each chunk sequentially and then concatenates the imputed chunks back. This caps the memory usage across different chromosomes (memory requirement is based on chunk size, not chromosome size). The length of the chunk and the overlap can be controlled by the <code>--chunkLengthMb</code> and <code>--chunkLengthOverlapMb</code> options, although we recommend using the default values.
* '''Approximations - ''' Minimac4 uses some simple approximations to speed up the imputation analyses. The levels of approximation can be controlled by the parameters <code>--probThreshold</code>, <code>--diffThreshold</code>, and <code>--topThreshold</code> (details given in Minimac4 Usage). Higher values of approximation will reduce the compute time but also marginally reduce the imputation accuracy. We recommend using the default values (= 0.01).