The period of this generator is 
, which can be of order 
for combining two 32-bit LCGs, which is adequate for current computers.
A Gigaflop-year is 
flops.
Empirical tests show no d-tuple lattice structure or
correlations in the sequence for the combined generator.
The period and randomness properties could be improved by using two 48-bit or 64-bit LCGs instead of 32-bit generators.
The authors of the Numerical Recipes books suggest that this generator, combined with a shuffling procedure to further reduce any possible correlations, has ``perfect'' randomness properties, with perfect defined as ``we will pay $1000 to anyone who convinces us otherwise (by finding a statistical test that [this generator] fails in a non-trivial way, excluding the ordinary limitations of a machine's floating point representation).''